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We report a case of two patients with foot drop due to peroneal nerve infarct as early sign of two different forms of primary systemic vasculitides: a predominantly small-vessel p-antineutrophil cytoplasmic antibody-positive vasculitis (microscopic polyangiitis) and a predominantly medium-vessel vasculitis (polyarteritis nodosa).

Objective: Detection of nerve enlargement in polyneuropathies by sonography is a new research area. No systematic investigation has been done yet in chronic inflammatory demyelinating polyneuropathy (CIDP). Therefore we investigated this in CIDP., Methods: Eleven patients with CIDP fulfilling the international criteria on CIDP underwent ultrasonographic examination of the median, ulnar, fibular and posterior tibial nerves and sometimes the brachial plexus bilaterally, using a standardized protocol. We assessed presence of nerve thickening and increased nerve vascularization., Results: In 7 of the 11 patients multiple nerve enlargements were detected: ulnar nerve 7, fibular nerve 5, posterior tibial nerve 4 and median nerve in 4 patients. The number of enlarged nerves was related with the MRC sum-score (p=0.03) and the total protein in the cerebrospinal fluid (CSF) at diagnosis (p=0.02). Increased vascularization was seen in 6 of the 11 patients: 4 in one nerve and in 2 in multiple nerves. The number of nerves with increased vascularization was associated with the number of enlarged nerves (p=0.01) and total protein in the CSF (p=0.006)., Conclusion: Multiple nerve enlargements occur in CIDP showing a relation with a lower MRC sum-score, increased nerve vascularization and a higher total protein of the CSF., Significance: Our findings of nerve enlargement and increased nerve vascularization may be tools to monitor disease activity in CIDP, but further studies are needed., (Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

The aim was to investigate the arterial supply of the sciatic, tibial, and common peroneal nerves. Thirty-six lower limbs of 18 human fetuses were studied. The fetuses had been fixed in buffered formalin and the blood vessels injected with barium sulfate. Fetal age ranged from 12 to 28 weeks of gestation. Microdissection of the fetal lower extremities was done under ×5 magnifying lenses. The sciatic nerves of 10 lower extremities were dissected and excised and radiographs taken. The extraneural arterial chain of the sciatic nerve was composed of 2-6 arterial branches of the inferior gluteal artery, the medial circumflex femoral artery, the perforating arteries, and the popliteal artery. The extraneural arterial chain of tibial nerve was composed of 2-5 arteries, which were branches of the popliteal, the peroneal, and the posterior tibial arteries. Radiographs showed the presence of complete intraneural arterial chains in the sciatic and tibial nerves, formed from anastomosing vessels. Dissection showed that, in 97.2% of the specimens, the common peroneal nerve was supplied only by one popliteal artery branch, the presence of which was confirmed radiologically. The sciatic and tibial nerves are supplied by numerous arterial branches of different origins, which provide for collateral circulation. In contrast, the common peroneal nerve is most frequently supplied only by one elongated longitudinal blood vessel, a branch of the popliteal artery. Such a vascular arrangement may make the common peroneal nerve less resistant to stretching and compression., (Copyright © 2012 Wiley Periodicals, Inc.)

Purpose: To compare the degree of neural regeneration in rats upon interposition of autologous nerve graft, autogenous vein, glycerol-preserved autogenous vein, and glycerol-preserved allogeneic vein using qualitative and quantitative histological analyses as well as functional assessments., Methods: Peroneal nerves were reconstructed differently in four groups of animals. Functional assessments were performed pre- and postoperatively for a period of six weeks. After six weeks, the animals were sacrificed and histological evaluations were performed., Results: Histological patterns of autogenous veins without preservation showed pronounced neoangiogenesis and extensive axonal rarefaction, as confirmed by axonal counting and functional assessments. Glycerol-preserved veins had results similar to the control., Conclusions: Glycerol-preserved autogenous or allogeneic veins showed similar results to autograft results. The autogenous vein (without preservation in glycerol) presented histological and functional outcomes statistically lower than other groups.

A 56-year old gentleman presented to our orthopaedic foot and ankle clinic, with unusual symptoms in his left foot. He described a tight sensation over his toes, "like sandpaper under his skin". The pain had started post operatively following a bilateral aorto-femoral bypass. He was subsequently investigated and found to have an ischemic lesion Identified in his common peroneal and posterior tibial nerve with associated muscle atrophy on EMG. This represents a previously unreported complication of aorto-femoral bypass surgery., (Copyright 2009. Published by Elsevier Ltd.)

Conventional reversed sural flaps have been used to cover lower one-third of the leg defects. However, the experience of the authors indicates that when the soft-tissue defect located at the dorsum of the metatarsophalangeal joint, distal marginal necrosis of the flaps usually occurs, which is the exact part of the flap that one needs the most. Finding a new method to augment the blood supply of the flap can be a difficult task. The authors found there is a constant cutaneous branch emanate from the peroneal artery at the point 11.0 +/- 1.7-cm upon the lateral malleolus. Ten modified distally based reverse sural artery flaps, in which the cutaneous branches from the peroneal artery 11.0 +/- 1.7-cm upon the lateral malleolus were added, were performed for the distal-third of the foot reconstruction between 2003 and 2006. All of the flaps survived completely after the operation. Distal marginal necrosis did not occur in any of the flaps. When conventional local flaps are inadequate, this flap should be considered for its reliability and low associated morbidity.

We tested the hypothesis that the intrinsic vascular plexus of the motor nerve could support viability in a rat hindlimb muscle flap. In a preliminary study, we examined the course and vascularity of the sciatic nerve, the peroneal nerve, and the peroneous longus muscle in the rat hindlimb via anatomic dissection, microangiography, and histologic study (n = 10 animals). On the basis of this examination, the peroneous longus muscle was chosen as our experimental model in this study. In 12 animals, the peroneus longus was acutely elevated, which severed all tendinous and vascular structures, this left the muscle pedicled on the motor nerve only (Group I). Animals in Group II underwent a staged elevation of the flap with division of the vascular pedicle, the tendon of insertion, and the tendon of origin during separate procedures that were 5 days apart (n = 12). Muscle viability was evaluated by gross inspection, measurement of muscle weight and length, nitroblue tetrazlium (NBT) staining, microangiography, and histology. NBT staining demonstrated that immediate elevation of the peroneus longus muscle flaps led to an average necrotic area of 80.6% +/- 9.8% (Group I). A significant improvement in viability was observed for muscle flaps of animals in Group II, with peroneus longus muscle necrosis averaging 25.6% +/- 9.3%. Microangiography demonstrated that the intrinsic vascularity of nerve was increased dramatically in Group II. These data support the hypothesis that the intrinsic vascular plexus of the motor nerve of a skeletal muscle can support at least partial viability of a muscle flap. However, this vascular axis is inadequate to support complete viability of a muscle flap if the flap is elevated immediately. If a staged elevation affects a surgical delay, the viability of a muscle flap elevated on a neural pedicle can be increased significantly. With adjustments in the delay procedure, this strategy may allow transfer of muscle flaps when maintenance or reconstitution of the primary vascular axis is not possible., ((c) 2009 Wiley-Liss, Inc.)

A distally based tenosynovial sheath of peroneal tendons was used as a flap with skin graft to cover the exposed tendo Achilles. The flap has a reliable blood supply being perfused by a constant sizeable musculofascial perforator. Cadaveric dissection with methylene blue dye study has been conducted to prove the rationality and reliability of blood supply. The position of the perforator had been confirmed prior to surgery by a hand-held Doppler. The flap used to cover the exposed Achilles tendon in five cases yielded positive results. To our knowledge, a retrograde flap of this nature is unprecedented though an antegrade flap of similar composition has been described.

Objective: The pathogenesis of diabetic peripheral neuropathy (DPN) is poorly understood. We have recently reported a significant reduction in spinal cord cross-sectional area at the stage of clinically detectable DPN. In this study, we investigated whether spinal cord atrophy occurs in early (subclinical) DPN., Research Design and Methods: Eighty-one male type 1 diabetic subjects, 24 nondiabetic control subjects, and 8 subjects with hereditary sensory motor neuropathy (HSMN) type 1A underwent detailed clinical and neurophysiological assessments. Diabetic subjects were subsequently divided into three groups based on neuropathy severity (19 with no DPN, 23 with subclinical DPN, and 39 with clinically detectable DPN). All subjects underwent magnetic resonance imaging of the cervical spine and cord area measurements at disc level C2/C3., Results: Mean corrected spinal cord area index (SCAI) (corrected for age, height, and weight) was 67.5 mm [95% CI 64.1-70.9] in diabetic subjects without DPN. Those with subclinical (62.4 mm [59.5-65.3]) and clinically detectable DPN (57.2 mm [54.9-59.6]) had lower mean SCAIs compared with subjects with no DPN (P = 0.03 and P < 0.001, respectively). No significant difference was found between diabetic subjects without DPN and nondiabetic control subjects (69.2 mm [66.3-72.0], P = 0.47). Mean SCAIs in subjects with HSMN type 1A (71.07 mm [65.3-76.9]) were not significantly different from those for nondiabetic control subjects and diabetic subjects without DPN. Among diabetic subjects, SCAI was significantly related to sural sensory conduction velocities and the Neuropathy Composite and Symptom Scores., Conclusions: Spinal cord involvement occurs early in DPN. There is also a significant relation between reduction in SCAI and neurophysiological assessments of DPN.

We investigated the blood supply of the common peroneal nerve. Dissection of 19 lower limbs, including six with intra-vascular injection of latex, allowed gross and microscopic measurements to be made of the blood supply of the common peroneal nerve in the popliteal fossa. This showed that a long segment of the nerve in the vicinity of the fibular neck contained only a few intraneural vessels of fine calibre. By contrast, the tibial nerve received an abundant supply from a constant series of vessels arising directly from the popliteal and posterior tibial arteries. The susceptibility of the common peroneal nerve to injury from a variety of causes and its lack of response to operative treatment may be explained by the tenuous nature of its intrinsic blood supply.

After harvesting of the sural nerve, the patient developed a partial palsy of the common peroneal nerve due to a lesion of the peroneal nerve and a neuroma of the sural nerve stump. Motor function recovered after performing neurolysis of the common peroneal nerve and mobilization of the neuroma. The sural nerve, in this case originating from the common peroneal nerve, was harvested using a nerve stripper and four small skin incisions. Direct lesion by the forced use of the nerve-stripping instrument followed by the formation of a neuroma close to the peroneal nerve are the suspected reasons for motor dysfunction. Although many authors report using a nerve stripper as a safe, less invasive method to gain nerve material for transplantation, we recommend lengthening the skin incision so as to be aware of anatomical variations and to refrain from pulling the nerve distally to avoid the described complications.

The lateral supramalleolar flap (LSMF) is frequently used for covering major tissue defects of the foot and ankle but usually, in case of arteriopathy of the lower limbs, this device is contra-indicated. Twenty-four specimens of amputated limbs of patients suffering from arteriopathy of the lower limbs allowed us to study the vascular anatomy of this flap after intra-arterial injection of colored latex. At the time of the amputation the average age of the patients was 68.5 years. The clinical signs of arteriopathy had been present for 3-16 years. In 10 cases the amputation was performed directly, in 14 cases after an unsuccessful attempt at revascularization. The dissection results revealed certain specificities in the vascularization of the LSMF with arteriopathy. The perforating branch of the peroneal artery was found in all cases. The descending branch of this perforating artery was found to be patent in 22 cases but slim in five cases. It was absent in two cases. The superficial peroneal nerve and its vascular network always participated in the vascularization of the flap. Thus, its preservation in the distal part of the flap offers a second vascular flow to the pedicle of the LSMF. This specificity increases the theoretical feasibility of the LSMF from 17 to 22 cases out of 24 in our dissections. The authors suggest a theory according to which the evolution of arteriopathy and the gradual concomitant development of a supply network, which effects the vascularization of the sensory nerves too, induces the "anticipation" of a flap. The preliminary distal revascularization by bypass grafts or by some kind of endovascular treatment should guarantee the good vascularization of a limb and the reliable use of this neurocutaneous arterial network.

Infiltration of activated lymphocytes and monocytes is a key phenomenon in the pathogenesis of Guillain-Barré syndrome (GBS) and experimental autoimmune neuritis (EAN). To investigate the role of chemokines, we determined the blood and nerve tissue expression of monocyte chemoattractant protein 1 (MCP-1), a major chemoattractant of monocytes and activated lymphocytes, and its receptor CCR2 in GBS and EAN. MCP-1 circulating levels (ng/ml) in GBS were increased at the time of progression, peaked at the time of plateau and normalized with recovery. MCP-1 circulating levels were the highest in the most disabled patients. The number of circulating CCR2 positive cells was lower in patients with GBS than in healthy subjects (p<0.004). In GBS, MCP-1 expression was observed in epineurial and endoneurial vessels, on infiltrating cells, Schwann cells and in the endoneurial extracellular matrix. Some CCR2 positive cells were observed in nerve biopsies of GBS patients. In EAN, a slight positivity for MCP-1 was observed in the sciatic nerve. There was no circulating CCR2 positive cells. However, at the time of plateau, a conspicuous infiltration of CCR2 positive cells was observed in the sciatic nerve that was no longer observed at the time of recovery. These results suggest that MCP-1 and CCR2 may participate to the recruitment of circulating mononuclear cells in nerve tissue in EAN and GBS.

It was the purpose of this study to evaluate the revascularization of primary nerve repair and grafts using orthogonal polarization spectral (OPS) (Cytometrix, Inc.) imaging, a novel method for real-time evaluation of microcirculatory blood flow. Twenty male Sprague Dawley rats (250 g) were anesthetized with vaporized halothane and surgically prepared for common peroneal nerve resection. Group I animals (n = 10) underwent primary neurorraphy following transection, utilizing a microsurgical technique with 10-0 nylon suture. Group II (n = 10) animals had a 7-mm segment of nerve excised, reversed, and subsequently replaced as a nerve graft under similar techniques. All animals were evaluated using the OPS imaging system on three portions (proximal, transection site/graft, and distal) of the nerve following repair or grafting. Reevaluation of 5 animals randomly selected from each group using the OPS imaging system was again performed on days 14 and 28 following microsurgical repair/grafting. Values were determined by percent change in vascularity of the common peroneal nerve at 0 hr following surgery. Real-time evaluation of blood flow was utilized as an additional objective criterion. Percent vascularity in group I and II animals increased from baseline in all segments at day 14. By day 28, vascularity in nerves of group I rats decreased in all segments to values below baseline, with the exception of the transection site, which remained at a higher value than obtained directly after surgical repair. In group II animals, vascularity remained above baseline in all segments except the distal segment, which returned to vascularity levels similar to those at 0 hr. Further, occlusion of the vessels demonstrated in the graft and distal segments following initial transection appeared to be corrected. This study suggests that revascularization may occur via bidirectional inosculation with favored proximal vascular growth advancement. The use of real-time imaging offers a unique evaluation of tissues through emerging technologies., (Copyright 2003 Wiley-Liss, Inc.)

Intensive diabetes treatment causes a considerable increase in the number of severe hypoglycaemic episodes which could aggravate the progression of diabetic neuropathy. However, the effect of repeated hypoglycaemic episodes on nerve morphology has never been previously investigated. The aims of the present study were: (i) to establish a rat model of recurrent episodes of severe hypoglycaemia, and (ii) to assess morphological changes after repeated hypoglycaemic episodes in rat sciatic nerves. We induced hypoglycaemic episodes, blood glucose level <3.0 mmol/l for 3 h, by injecting regular insulin intravenously on 4 consecutive days. We found endothelial swelling of endoneurial microvessels at the thigh level of sciatic and tibial nerves 24 h after four daily episodes of hypoglycaemia. Endothelial swelling was confirmed by vascular morphometry which showed significantly increased endothelial and pericyte areas. No obvious abnormalities were seen on nerve fibres. In conclusion, recurrent hypoglycaemic episodes cause early vascular anomalies in endoneurial microvessels in rat sciatic nerves without any observable changes in nerve fibres.

This study included 25 patients with lower limb tumors who had reconstruction by vascularized fibula osteoseptocutaneous flap performed at least 24 months before the end of the study. Hypertrophy of the transplanted fibula was estimated on serial radiographs by a modification of the formula of De Boer and Wood (J Bone Joint Surg [Br] 71:374-378, 1989). A significant graft was observed in 90% of the patients at an average follow-up of 27 months (range, 30-200%). The time to graft union (start of partial weight-bearing) positively correlated with the time to significant graft hypertrophy (r = 0.9, P < 0.01). The final amount of graft hypertrophy was affected by the age of the patient (P < 0.01) and the length of follow-up (P < 0.05). Graft hypertrophy progressed at an average rate of 3.3% per month (range, 2.3-4.9%) until the end of the 30th month; thereafter, little or no increase in graft hypertrophy was observed. The rate of graft hypertrophy showed two significant peaks at 6-12 months (P < 0.001) and at 18-24 months (P < 0.05). Patients younger than age 20 years showed faster hypertrophy, with a peak at the 12th month. Hypertrophy progressed faster in patients who received chemotherapy until the 12th month, and then declined sharply compared to those who did not receive chemotherapy., (Copyright 2002 Wiley-Liss, Inc. MICROSURGERY 22:367-370 2002)

Devascularized bone grafts are pieces of dead bone and they simply serve as scaffolds for new bone to grow and fill the gap, taking a long time when they succeed in doing so. In contrast, vascularized grafts being living tissues have short healing time, great vitality and strong infection-resisting capacity. We report here the successful use of vascularized grafts of the lower end of fibula for fusing the ankle in five leprosy patients.

Objectives/hypothesis: Develop an hypoxic peripheral nerve injury model with a controlled injury type and two types of clinically relevant physiological measurements of function during and after recovery. The model, controlling for injury and measurement variables, would have predictable outcomes in function. The functional model could test potential therapeutic interventions with greater sensitivity., Study Design: Twenty-one rats were used in preliminary studies evaluating peroneal nerve injury types and functional model evaluation. Forty-eight rats were used in a controlled and blinded evaluation of the injury model followed by treatment with hyperbaric oxygen (HBO) as a potential therapeutic intervention and evaluated with functional models., Methods: Preliminary studies compared nerve injuries: epineurectomy, epineurectomy with crush and transection with autograft for rate of return of function and final extent of return of function. The gait analysis model was also evaluated and modified to decrease variability. The final study evaluated peroneal epineurectomy and nerve crush injury with serial gait analysis during recovery, final elicited maximum force measurements, and histological analysis. Half of the animals were treated with HBO during recovery (ANOVA or regression statistical analysis were used to determine group differences.)., Results: Preliminary studies suggested that the peroneal nerve injury model of an epineurectomy with crush of specified length and a modification of the gait analysis model would yield a useful and predictable injury outcome. The final study resulted in predicted and consistent injury outcomes. In the HBO treatment group, a 12% improvement in function 5 days after HBO treatment was demonstrated (P < .03), but no long-term or histological benefit was seen., Conclusion: A reliable hypoxic nerve injury model has been developed and tested utilizing two functional methods as the primary outcome variables.

The revascularization of nerve grafts was investigated using histologic and morphometric techniques. Small-diameter nerve grafts (sciatic in the rat and sural in adult ewes) were studied, as was a large-diameter peroneal nerve graft in the ewe. Ninety-six hours after sciatic nerve engraftment, rats were injected with an intravascular fluorescent tracer. Evans blue albumin (EBA). Specimens were observed for the number of vessels perfused. Analysis showed no difference in vascular pattern between the grafted nerves and their control nerves, suggesting that spontaneous revascularization had occurred to establish a vascular tree essentially identical to the native nerve. Sural and peroneal nerve grafts were evaluated in adult ewes at 7 or 40 days post-nerve grafting. Similar to the rat sciatic nerve, the small-diameter sural nerve grafts were completely revascularized, with an equal number of perfused vessels at both time periods, with respect to control specimens. In contrast, the larger-caliber peroneal nerve grafts were not perfused at 7 days, and very poorly perfused at 40 days. This correlated with scant neural regeneration at 40 days. The finding suggests that small-diameter nerve grafts spontaneously revascularize, and revascularization using microvascular techniques is not necessary. In contrast, the larger-diameter nerve graft did not revascularize well. Such a large-diameter nerve graft would provide a suitable model to investigate the potential merits of a vascularized nerve graft.

The present study was carried out on 30 cadavers (5 fresh, 20 preserved adult and 5 fresh stillborn) following injection of red latex through the subclavian and common iliac arteries. The blood supply to the peripheral nerves was studied in general, together with the vascular pedicles to the ulnar, saphenous, sural, deep and superficial peroneal nerves, and the superficial branch of the radial nerve. The nutrient arteries supplying the peripheral nerves came from either the adjacent axial artery or the fasciocutaneous or muscular arteries. They formed anastomotic channels in the epineurium and penetrated it to form a continuous longitudinal artery. Based on the presence of absence of dominant arterial pedicles, five patterns of blood-supply to the nerves could be identified. I: no dominant arterial pedicle; II: only one dominant artery (e.g. artery with a diameter more than 0.8 mm and accompanying the nerve for most of its length); III: only one dominant vessel that divided into ascending and descending branches to supply the nerve; IV: multiple dominant pedicles; V: multiple dominant arterial pedicles forming a continuous artery that accompanied the nerve. The arterial pedicles to the ulnar, saphenous and deep peroneal nerves and the superficial branch of the radial n. had mean diameters of over 0.8 mm, thus being suitable for microvascular anastomosis. Those to the sural nerve were not present in two thirds of the dissected cadavers. In 10% of the cadavers the superficial peroneal nerve had an arterial pedicle that accompanied the nerve for less than two cm with a mean diameter less than 0.8 mm. The ulnar nerve could be very suitable as a donor vascularized nerve graft as it had a dominant vascular pedicle in all the cases studied; however, its use should be restricted to C8 and T1 root damage of the brachial plexus. The superficial branch of the radial n. might be suitable for vascularized nerve grafting, but this is difficult in practice since the radial artery is a major limb artery. The saphenous nerve had a dominant arterial pedicles in all the cadavers dissected and could be the most suitable as a donor vascularized nerve graft, unlike the sural nerve which did not have a dominant arterial pedicle in two-thirds of the specimens. The deep and superficial peroneal nerves may also be unsuitable since the former is accompanied by a major limb vessel while the latter had a dominant vascular pedicle that accompanied the nerve for only a short distance in 10% of the dissected cadavers.

To characterize the morphology of the endoneurial microvasculature of degenerating nerves under hyperglycemia, the morphology of endoneurial microvessels in transected sciatic nerves was examined in normal and streptozotocin-induced diabetic rats. Three months after transection, the fascicular area and median vascular luminal area at the proximal level of the distal stump were significantly larger in diabetic than in control animals, whereas the number of vessels per fascicle was the same in the two groups. Arterioles in various stages of development were found in the centrifascicular region in some transected nerves. Serial sections revealed that these vessels originated from transperineural arterioles. The frequency and magnitude of vascular wall thickening were both greater in diabetic rats. These results suggest that the endoneurial microvasculature responds abnormally to nerve injury under hyperglycemia.

Background: Reflex sympathetic dystrophy (RSD) (recently reclassified as complex regional pain syndrome type I) is a syndrome occurring in extremities and, when chronic, results in severe disability and untractable pain. RSD may be accompanied by neurologic symptoms even when there is no previous neurologic lesion. There is no consensus as to the pathogenic mechanism involved in RSD. To gain insight into the pathophysiology of RSD, we studied histopathology of skeletal muscle and peripheral nerve from patients with chronic RSD in a lower extremity., Methods: In eight patients with chronic RSD, an above-the-knee amputation was performed because of a nonfunctional limb. Specimens of sural nerves, tibial nerves, common peroneal nerves, gastrocnemius muscles, and soleus muscles were obtained from the amputated legs and analyzed by light and electron microscopy., Results: In all patients, the affected leg showed similar neurologic symptoms such as spontaneous pain, hyperpathy, allodynia, paresis, and anesthesia dolorosa. The nerves showed no consistent abnormalities of myelinated fibers. In four patients, the C-fibers showed electron microscopic pathology. In all patients, the gastrocnemius and soleus muscle specimens showed a decrease of type I fibers, an increase of lipofuscin pigment, atrophic fibers, and severely thickened basal membrane layers of the capillaries., Conclusion: In chronic RSD, efferent nerve fibers were histologically unaffected; from afferent fibers, only C-fibers showed histopathologic abnormalities. Skeletal muscle showed a variety of histopathologic findings, which are similar to the histologic abnormalities found in muscles of patients with diabetes.

Using a computer-assisted threshold hunting paradigm the motoric threshold of the common peroneal nerve was monitored in 18 patients during a high tibial osteotomy (HTO). The exposed nerve (lateral approach) was stimulated proximal to the osteotomy area and the surface EMG of the M. tibialis anterior was used to guide a threshold hunting device. Motoric threshold as a sensitive indicator of nerve function was found to be almost unaffected by several surgical steps of HTO. Only forceful rotation of a subperiostal Hohmann device during high peroneal osteotomy evoked a slight threshold shift that was fully reversible with device repositioning. The tourniquet, however, affected the threshold significantly. In 10 of the 18 patients the nerve became completely inexcitable after an average time of 59 min. The inexcitability was reversible after opening of the tourniquet. On the other hand, the eight patients maintaining an excitability throughout the entire ischemic period had tourniquet times that did not exceed 60 min. There are several factors that may be responsible for the observed inexcitability after long ischemic periods and we conclude that tourniquet time minimization appears appropriate to avoid neurological deficits during a high tibial osteotomy.

An ideal donor site for vascularized nerve grafts should have a constant anatomy, minimal functional loss after the nerve has been sacrificed, and a dependable blood supply parallel to the nerve over a relatively long distance. Creating a pedicle for a free vascularized deep peroneal nerve graft with the anterior tibial vessels seems to be a most suitable method for repairing long nerve gaps of over 20 cm and digital nerve defects with severe finger damage. Applications of this nerve graft to digital nerve losses with severely scarred beds created by avulsion injury, and two-stage reconstruction in some partial brachial plexus palsies (free vascularized nerve graft in the first stage and free vascularized muscle graft in the second stage) are well indicated. Advantages of this technique are: (1) A long nerve graft (up to 25 cm) can be obtained, and anomalies are rare (the nerve is absent in only 4 percent of cases). (2) The caliber of the vascular pedicle is large (approximately equal to 3 mm). (3) The nerve has a sufficient blood supply from the collateral blood vessels. (4) The graft can be easily obtained in the supine position. (5) A monitoring skin flap, based on the inferior lateral peroneal artery, can be attached to the nerve graft. (6) Sensory loss resulting from the sacrifice of the nerve covers a minimal area. (7) A donor scar on the anterior aspect of the lower leg is more acceptable than one on the posterior aspect because of less movement in walking. Disadvantages of this technique are: (1) Sacrifice of the large vessels in the lower leg may result in circulatory complications in the donor foot; to avoid this problem, preoperative angiography is recommended. (2) The donor scar is in an exposed area in female patients. (3) There may be temporary postoperative edema and disability in the donor leg.

Nerve ischaemia plays a major role in the development of pathological alterations in various neuropathies, and the effects of ischaemia are amplified by reperfusion in various tissues. While pathological alterations in acutely ischaemic nerve have been established, nerve pathology resulting from reperfusion injury has never been elucidated. To evaluate what cell type in peripheral nerve is affected by reoxygenation following a hypoxic episode, we developed an animal model of transient severe limb ischaemia. Near-complete ischaemia, confirmed by the measurement of nerve blood flow, was achieved by clamping multiple arteries of supply to rat hindlimb. After 3, 5 or 7 h of limb ischaemia, vascular clips were released to reperfuse blood flow. Pathology in sciatic, tibial and peroneal nerves at the lower thigh level was examined at 7 d after reperfusion. All reperfused nerves developed demyelinated nerve fibres, particularly in perivascular regions. Although 3 h of ischaemia followed by reperfusion caused demyelination, perivascular demyelination was more prominent after a longer period of ischaemia with reperfusion. Two types of nerve oedema were observed; endoneurial oedema especially in perivascular and subperineurial spaces, and intramyelinic oedema. Nerve fibres with intramyelinic oedema were not confined to the perivascular region. Swollen endothelial cells in endoneurial vessels were also invariably observed. Nerve ischaemia per se, without reperfusion, did not induce these pathological changes. Because myelin appears to be particularly susceptible to activated free radicals, oxidative stress, activated neutrophils, and cytokine formation seem to be important underlying mechanisms in the development of perivascular demyelination and intramyelinic oedema in ischaemic/reperfused nerves.(ABSTRACT TRUNCATED AT 250 WORDS)

1. The aims of this study were first, to examine whether deficits in nerve conduction in streptozotocin-diabetic rats could be reversed by a 10% dietary supplement of evening primrose oil. Second, to determine the time-course of reversal, and third, to assess whether the effects could be blocked by the cyclo-oxygenase inhibitor flurbiprofen (5 mg kg-1 day-1). 2. One-month diabetes produced 20% and 15% deficits in sciatic motor and saphenous sensory conduction velocity respectively, which were maintained over 2 months diabetes. 3. The effect of 1-month evening primrose oil treatment on abnormalities caused by an initial month of untreated diabetes was examined. Motor and sensory nerve conduction velocity were restored to the non-diabetic level. 4. Resistance to hypoxic conduction failure was investigated for sciatic nerve trunk in vitro. The 80% conduction failure times were 29% and 55% prolonged by 1- and 2-month diabetes respectively. Evening primrose oil did not reverse the increased hypoxic resistance following 1-month untreated diabetes. 5. Sciatic nerve endoneurial capillary density was not significantly affected by diabetes, but was 16% increased in diabetic rats with reversal by evening primrose oil treatment for 1 month compared to 2-month untreated diabetes. 6. Serial motor conduction velocity measurement after 3-month untreated diabetes revealed complete normalization by evening primrose oil within 4 days. Cessation of treatment resulted in a rapid decline in conduction velocity over 24 h. 7. In a preventive study of 2-month duration, 6 groups of rats were used. These comprised non-diabetic controls, diabetic rats, and evening primrose oil-treated diabetic rats, both with and without flurbiprofen treatment. Flurbiprofen had no significant effect in non-diabetic rats, but produced an 11% worsening of motor conduction velocity and a 21% reduction of sciatic capillary density in diabetic rats. Evening primrose oil prevented the decreases in conduction velocity and increased hypoxic resistance with diabetes, and caused a 23% increase in capillary density. Flurbiprofen completely blocked the effect of evening primrose oil on conduction velocity, resistance to hypoxia, and capillarization.8. Six main conclusions were reached. First, evening primrose oil rapidly reverses conduction deficits in diabetic rats. Second, the effects of treatment may be very short-lived, suggesting a primary metabolic action. Third, evening primrose oil cannot reverse established changes in hypoxic resistance over 1-month treatment. Fourth, long-term treatment causes angiogenesis, suggesting a vascular action. Fifth,products of cyclo-oxygenase-mediated metabolism are necessary for maintaining vasa nervorum integrity in diabetic rats. Sixth, evening primrose oil probably acts by providing substrate for vasodilator prostanoid synthesis by vasa nervorum.

An anatomic study performed on 64 fresh injected legs has shown the role of the vascular axis that follows the superficial sensitive nerves in supplying the skin. Three nerves were studied: the saphenous nerve, the superficial peroneal nerve, and the sural nerve. Conclusions are the same for the three nerves: The vascular axis, which can be either a true artery or an interlacing network, ensures the vascularization of the nerves, gives off several cutaneous branches in the suprafascial course of the nerve, and anastomoses with the septocutaneous arteries issuing from a deep main vessel. The superficial nerves that course the leg can therefore be considered as vascular relays owing to their neurocutaneous arteries. The concept of a neuroskin island flap has been developed and applied to six clinical cases for coverage of some specific areas of the knee and of the lower part of the limb.

The clinical picture is described of 4 patients with the syndrome of lesion of the peroneal developing during fixation of some physiological postures (squatting position etc.). The pathogenetic mechanisms of the disease are discussed. The authors report a characteristic monotypical clinical symptom complex of compression-ischemic peroneal neuropathy.

The reasons for the resistance to ischaemia of peripheral nerves in diabetics are not well understood. We have now explored whether axonal depolarization underlies this phenomenon, as has previously been proposed. Resistance to ischaemia was determined by the new method of "threshold tracking". This method revealed an increase in excitability of the peroneal nerve at the popliteal fossa during ischaemia, and a decrease in excitability in the post-ischaemic period. The extent of these alterations in 28 type 1 diabetics without peripheral neuropathy showed a strong correlation with the mean blood glucose concentrations during the last 24 h before examination. To test whether the ischaemic resistance was related to membrane potential, we also measured axonal superexcitability in 11 selected diabetics, since it has been shown that post-spike changes in excitability depend on membrane potential. Changes in excitability of the peroneal nerve were measured in the period between 10 and 30 msec following a conditioning supramaximal compound action potential. Under resting conditions, no differences in the post-spike superexcitability were found between controls and diabetics, despite striking differences in their responses to a 10-min pressure cuff. These observations indicate that membrane depolarization is not involved in the resistance to ischaemia of motor axons in diabetic subjects.

A 49-year-old man presented with temperature up to 39.5 degrees C, a sudden peroneal nerve lesion, and a cardiac murmur. The peroneal nerve lesion was likely caused by an embolic occlusion of an artery supplying the nerve. Until now, six cases of embolic mononeuropathy in endocarditis have been reported in the literature. Embolic mononeuropathy is a very rare manifestation of subacute bacterial endocarditis and quite often complicates, as do other more common embolic manifestations, the correct diagnosis.

The authors discuss their experience in the Division of Plastic and Hand Surgery of the Hospital of Legnano in the treatment of lesions of the sciatic nerve treated by microsurgery and in some cases by nerve grafts. The results obtained were assessed as acceptable in terms of function of the lower limb. Twenty-two cases were followed up, of which 13 had been treated by neurolysis and 9 with nerve grafts. The thigh muscles recovered in all cases, together with muscles innervated by the tibial nerve in 18 cases and the muscles innervated by the peroneal nerve in 13 cases.

The transverse section of the sciatic, tibial and peroneal nerves in rabbits was followed by mobilization in a proximal and distal direction and a tension-free end-to-end suture of the cut surfaces. The proximal mobilization was performed up to eight different levels between 60 mm and 200 mm, i. e. 20.3% to 67.7% of the total nerve length. Histological findings and their statistical analysis indicated that the critical mobilization length, beyond which ischaemic parenchymal damages occur, is 70 mm or 24% of the total nerve length. Up to this level, the vascular "extrinsic system" of the mobilized nerve segments is completely compensated for by the "intrinsic system". When the mobilization length is increased, the degeneration distances were more pronounced than those of the ischaemic nerve distances. Some nerves showed no effects from the ischaemia.

Forty-three patients with post-traumatic paralysis of the peroneal communicating nerve were followed up and photographed after a mean period of 5 years (range: 2 1/2 to 10 1/2 years). The interest of the study lies in the possibility of comparing clinical and electromyographic findings in 31 cases, enabling establishment of prognostic factors, and of evaluating results of posterior tibial muscle transpositioning after more than 5 years (12 cases).

Endoneurial edema occurs in numerous human and experimental neuropathies. We tested the hypothesis that the resultant increase in intercapillary distance (ICD) may result in endoneurial hypoxia. Experimental galactose neuropathy (EGN) was chosen since in this model, edema is due to the accumulation of galactitol, which does not directly damage nerve fibers, so that it was possible to study the role of endoneurial edema alone. We measured endoneurial oxygen tensions (PnO2) using oxygen-sensitive microelectrodes and related PnO2 radial topography to ICD. We also determined local oxygen consumption (VLO2) and critical PnO2(PcritO2). EGN and age-matched controls were studied at 4 months. (1) Caudal nerve conduction velocity was reduced in EGN. (2) The PnO2 values were reduced in EGN and the PnO2 histogram was shifted into the hypoxic range. These changes were paralleled by a significant increase in ICD in EGN. (3) The radial topography of PnO2 in EGN differed from the relatively uniform distribution in control nerves. In EGN the subperineurial PnO2 was significantly lower than the PnO2 at the center of the fascicle. These changes were paralleled by a significantly greater increase in ICD in the periphery. (4) That the PnO2 reduction in EGN was significant is suggested by the marked reduction in VLO2 and the large percentage (greater than 75%) of intrafascicular regions that fell below PcritO2 in EGN.

Satisfactory replacement of skin defects over the lower leg remains a difficult problem. Various forms of coverage, including, local rotation flaps, muscle flaps, and fascial and free flaps, have their specific indications and inherent disadvantages. In this work, a new axial skin flap based on perforating vessels in the territory of the anterior tibial artery is described. A series of 50 lower leg dissections was carried out in 25 fresh cadavers after latex injection into the femoral artery. Detailed studies of the cutaneous distribution of the anterior tibial artery showed that three main arteries perfuse the anterior lateral portion of the lower leg. The superior lateral peroneal artery and the inferior lateral peroneal artery interseptal cutaneous perforators arise at an average of 25.6 and 17.2 cm from the lateral malleolus, respectively. The superior lateral peroneal artery was present in 100 percent of the specimens, whereas the inferior lateral peroneal artery was present in 70 percent of the specimens. In their course, they give several muscular branches to the peroneus longus and brevis prior to perforating the fascia and arborizing in the subcutaneous tissues of the anterolateral portion of the leg. The average external diameter was 1.6 cm for the superior and 1.4 cm for the inferior lateral peroneal artery. The superficial peroneal nerve accessory artery is the third artery which contributes to the skin of the lower leg. It arises from the superior lateral peroneal artery in 30 percent of cases, from the inferior lateral peroneal artery in 40 percent, and from both in 30 percent. The artery runs along with the superficial peroneal nerve and gives several cutaneous perforators along its descending course. Several cutaneous axial flaps can be fashioned around this anatomy. The operative technique along with demonstrative clinical cases is presented followed by pertinent discussion.

Five cases of segmental vascularized nerve grafts that bridge scarred beds for digital sensory nerve reconstruction where previous nonvascularized nerve grafts have failed are reported. Average follow-up in this study was 27 4/5 months. Three patients were men and two were women. Average age was 35 1/2 years. The thumb was the recipient digit in one patient; the index finger in two patients; and the long finger in two patients (primary opposing digit). Three digits had suffered amputation and two had crush lacerations. Average graft length was 6.6 mm. Pin prick, touch, and vibratory sensation were restored in all patients (slightly impaired in one). Average moving two-point discrimination was 7.2 mm; average static two-point discrimination was 9.5 mm. Von Frey monofilament cutaneous pressure averaged 4.03 gm. Donor morbidity was negligible except for a neuroma in one patient and slight superficial skin loss in another.