A Giant Atypical Baker’s Cyst Causing Compressive Neuropathy of Combined Peroneal and Tibial Nerves - A Case Report

OBJECT Knee dislocations are often accompanied by stretch injuries to the common peroneal nerve (CPN). A small subset of these injuries also affect the tibial nerve. The mechanism of this combined pattern could be a single longitudinal stretch injury of the CPN extending to the sciatic bifurcation (and tibial division) or separate injuries of both the CPN and tibial nerve, either at the level of the tibiofemoral joint or distally at the soleal sling and fibular neck. The authors reviewed cases involving patients with knee dislocations with CPN and tibial nerve injuries to determine the localization of the combined injury and correlation between degree of MRI appearance and clinical severity of nerve injury. METHODS Three groups of cases were reviewed. Group 1 consisted of knee dislocations with clinical evidence of nerve injury (n = 28, including 19 cases of complete CPN injury); Group 2 consisted of knee dislocations without clinical evidence of nerve injury (n = 19); and Group 3 consisted of cases of minor knee trauma but without knee dislocation (n = 14). All patients had an MRI study of the knee performed within 3 months of injury. MRI appearance of tibial and common peroneal nerve injury was scored by 2 independent radiologists in 3 zones (Zone I, sciatic bifurcation; Zone II, knee joint; and Zone III, soleal sling and fibular neck) on a severity scale of 1-4. Injury signal was scored as diffuse or focal for each nerve in each of the 3 zones. A clinical score was also calculated based on Medical Research Council scores for strength in the tibial and peroneal nerve distributions, combined with electrophysiological data, when available, and correlated with the MRI injury score. RESULTS Nearly all of the nerve segments visualized in Groups 1 and 2 demonstrated some degree of injury on MRI (95%), compared with 12% of nerve segments in Group 3. MRI nerve injury scores were significantly more severe in Group 1 relative to Group 2 (2.06 vs 1.24, p < 0.001) and Group 2 relative to Group 3 (1.24 vs 0.13, p < 0.001). In both groups of patients with knee dislocations (Groups 1 and 2), the MRI nerve injury score was significantly higher for CPN than tibial nerve (2.72 vs 1.40 for Group 1, p < 0.001; 1.39 vs 1.09 for Group 2, p < 0.05). The clinical injury score had a significantly strong correlation with the MRI injury score for the CPN (r = 0.75, p < 0.001), but not for the tibial nerve (r = 0.07, p = 0.83). CONCLUSIONS MRI is highly sensitive in detecting subclinical nerve injury. In knee dislocation, clinical tibial nerve injury is always associated with simultaneous CPN injury, but tibial nerve function is never worse than peroneal nerve function. The point of maximum injury can occur in any of 3 zones.

Involuntary, Electrically Excitable Nerve Transfer for Denervation: Results From an Animal Model

To evaluate the diagnostic accuracy of diffusion tensor imaging (DTI) in diabetic peripheral neuropathy (DPN) for patients with type 2 diabetes and detect the correlations with electrophysiology. A total of 27 patients with type 2 diabetes with DPN, 24 patients with type 2 diabetes without peripheral neuropathy (NDPN), as well as 32 healthy controls (HC) were enrolled in this study. Clinical examinations and neurophysiologic tests were used to determine the presence of DPN. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of peripheral nerves, including the tibial nerve (TN) and common peroneal nerve (CPN), were calculated. Receiver operating characteristic (ROC) analysis was performed for FA and ADC values. Pearson's correlation coefficient was used to assess the correlation between DTI and electrophysiology parameters in the patient group. The tibial and common peroneal nerve FAs were lowest (P=0.003, 0.001, respectively) and ADC was highest (P=0.004, 0.005, respectively) in the DPN group. The FA value of the axonal injury group was lower than that in the demyelination group (P=0.035, 0.01, respectively), while the ADC value was higher (P=0.02, 0.01, respectively). In the DPN group, FA value was positively correlated with motor conduction velocity (MCV) (tibial nerve: r=0.420, P=0.007; common peroneal nerve: r=0.581, P<0.001) and motor amplitude (MA) (tibial nerve: r=0.623, P<0.001; common peroneal nerve: r=0.513; P=0.001), while ADC values was negatively correlated with MCV (tibial nerve: r=-0.320, P=0.044; common peroneal nerve: r=-0.569; P<0.001), and MA (tibial nerve: r=-0.491, P=0.001; common peroneal nerve: r=-0.524; P=0.001). With a lower FA value and higher ADC value, DTI accurately discriminated DPN. The DTI multi-parameter quantitative analysis of peripheral nerves differentiated DPN axonal injury from the demyelinating lesion, and hence, could be applied in the diagnosis of DPN.

Development and verification of saphenous, tibial and common peroneal nerve block techniques for analgesia below the thigh in the nonchondrodystrophoid dog

Introduction: The direction and magnitude of nerve mobility in the lower extremity has been quantified in fixed cadaveric tissue but extrapolation of findings to live humans is limited. Ultrasound is an emerging tool for in vivo imaging of soft tissues such as peripheral nerve. The purpose of this study was to investigate in vivo excursion of the tibial and common fibular nerves in the popliteal fossa during limb positioning in healthy participants.Methods: Real time ultrasound imaging of the tibial and common fibular nerves in the popliteal fossa was performed on 5 healthy subjects using a Siemens Acuson Sequoia machine. Imaging was performed while the ankle was moved through plantar and dorsiflexion in two hip positions.Results: The tibial nerve glided proximal, deep and lateral during plantar flexion and distal, superficial and medial during dorsiflexion. The common fibular nerve glided superficial and lateral during plantar flexion and deep and medial during dorsiflexion.Conclusions: The tibial and common fibular nerves have significant mobility in both the transverse and sagittal planes during ankle motion. The direction of proximal and distal excursion of the tibial nerve is consistent with previous cadaveric studies. Ultrasound imaging is an effective, non‐invasive way to investigate movement of the large peripheral nerves in the lower extremity.

Correlation between risk factors for diabetic peripheral neuropathy and nerve conduction study parameters in children with type 1 diabetes mellitus attending Sudan childhood diabetes centre

This case report describes an uncommon compressive neuropathy involving both the common peroneal and tibial nerves as they pass through the popliteal fossa. The patient is a 16-year-old male who sustained a right knee fracture-dislocation. There was disruption of the popliteal artery, which was repaired with a reversed saphenous vein graft. This surgery was complicated by a postoperative hematoma. After drainage of the hematoma, the patient developed a progression neuropathy over the next 6 months that involved the common peroneal nerve and to a lesser extent the tibial nerve. Foot drop, muscle wasting of posterior and anteriolateral compartment and sensory loss over the dorsal foot and lateral leg were also documented. Based on the history, clinical finding and electrodiagnostic studies, the patient had both a tibial and common peroneal neuropathy. The neuropathy was related to the accident, but the exact etiology was unknown prior to surgical exploration. Surgical exploration was performed 15 months following the injury after referral to our institution and thick fibrous scar tissue was found compressing both tibial and common peroneal nerves. These bands were released and complete internal neurolysis was performed on both nerves. Although uncommon, surgical nerve compression can occur following extensive scarring secondary to trauma or surgical procedures. This discussion will describe the history of compressive neuropathies in the popliteal fossa. We will review the relevant literature and anatomy of this disease and describe disease progression and treatment options.

Objective To investigate the characteristics of giant F-waves in patients with amyotrophic lateral sclerosis (ALS) and the relationship between giant F-waves and disease phenotype. Methods Motor nerve conduction study and F-waves were performed to the median, ulnar, tibial and peroneal nerves of 55 patients with ALS and 52 healthy volunteers. A series of 100 electrical stimuli were employed to obtain F-waves. The following F-wave variables were estimated: frequency of giant F-waves, frequency of patients with giant F-waves, the relationship between giant F-waves and lower motor neuron dysfunction, the relationship between giant F-waves and upper motor neuron dysfunction, the relationship between giant F-waves and disease duration, the relationship between giant F-waves and disease severity, and the relationship between giant F-waves and disease progression rate (DPR). Results The frequencies of giant F-waves (ALS: median nerve 0.00(0.00)%, ulnar nerve 0.00(1.02)%, tibial nerve 0.00(0.00)%, peroneal nerve 0.00(0.00)%. Normal controls: median nerve 0.00(0.00)%, Z=-2.360, P=0.018; ulnar nerve 0.00(0.00)%, Z=-3.997, P<0.01; tibial nerve 0.00(0.00)%, Z=-3.006, P=0.003; peroneal nerve 0.00(0.00)%, Z=-3.006, P=0.003) and the frequencies of patients with giant F-waves (ALS: median nerve 13/55, 23.6%, ulnar nerve 26/55, 47.2%, tibial nerve 18/55, 32.7%, peroneal nerve 16/55, 29.1%. Normal controls: median nerve 4/52, 7.7%, χ2=0.024, P=0.024; ulnar nerve 7/52, 13.5%, χ2=14.326, P<0.01; tibial nerve 6/52, 11.5%, χ2=6.897, P=0.009; peroneal nerve 6/52, 11.5%, χ2=5.042, P=0.025) in the median nerve, ulnar nerve, tibial nerve and peroneal nerve were significantly increased compared with those of the normal controls. No significant differences were found in the frequencies of upper motor neuron dysfunction between nerves with giant F-waves and nerves without giant F-waves in the median nerves, ulnar nerves, tibial nerves and peroneal nerves of ALS patients. The compound muscle action potential amplitude of nerves with giant F-waves was significantly higher than those of nerves without giant F-waves in the median nerves (11.20(5.80) mV vs 5.90(8.50) mV, t=2.883, P=0.004)and tibial nerves ((13.20±4.61) mV vs (10.69±4.76) mV, t=-2.222, P=0.028)of the ALS patients. No significant correlation was detected between the frequency of giant F-waves and disease duration or ALS functional rating scale in the ALS patients, while the frequency of giant F-waves correlated inversely with the DPR(r=-0.287, P=0.034). No significant differences were detected in disease duration between ALS patients with giant F-waves and those without giant F-waves. Compared with those in ALS patients without giant F-waves, the revised ALS Functional Rating Scale score (37.00(3.00) vs 42.00(4.75), Z=3.197, P=0.001) was more, the DPR (0.50(0.35)vs 0.90(0.43), Z=-3.033, P=0.002) was slower in ALS patients with giant F-waves. Conclusions The giant F-waves were significantly increased in the ALS patients than those in the healthy volunteers and were distributed asymmetrically between the left and right sides. These electrophysiological characteristics of ALS patients fitted well with progressive loss of anterior horn cells, and indicated differential involvement of different spinal motoneuron pools in the ALS patients. No correlations were found between the frequency of giant F-waves and disease duration. The appearance of giant F-waves may indicate loss of spinal motoneuron early in the disease course, and may suggest that the degree of reinnervation and functional compensation are relatively good after motoneuron loss. Key words: Amyotrophic lateral sclerosis; Neural conduction; F-wave

Objective To study the effect of using different tibial nerve proximal muscle branchs to repair deep peroneal nerve injury in animal experiment, and to screen out the most optimal donor nerve branch. Methods From June, 2016 to August, 2016, 64 adult female SD rats were randomly divided into 4 groups, which were LHG (using lateral head of gastrocnemius to repair peroneal nerve) , MHG (using medial head of gastrocnemius to repair peroneal nerve) , SNB (using soleus nerve branch to repair peroneal nerve) , and blank. There were16 rats in each group. At 4 and 8 weeks after surgery, each group were tested on behavior, electrophysiology, muscle tension, muscle wet weight and histology, to evaluate function recovery of the muscles controlled by deep peroneal nerve in each group, and to compare recovery of the deep peroneal nerve repaired by different tibial nerve branches. Results Eight weeks after surgery, right foot of the rats in LHG, MHG and SNB group can be extended, toes can be completely opened. Rats in blank group showed limping gait, whose right foot can not be extended, right toe can not be opened, and muscle atrophied. At 4 and 8 weeks after the operation, the recovery rate of LHG, MHG, SNB group (at 4th weeks, 33.60 ±2.22) % , 33.07 ±2.38% and 35.91 ±2.02% ; at 8th weeks, 67.16 ±5.74) % , 66.56 ±3.18% and 73.17 ± 5.33%, respectively) was higher than blank group (7.71±1.05% and 7.84±0.78%, respectively) on CMAP amplitude, tibialis anterior muscle contractility, tibialis anterior muscle cell area, muscle cell area. SNB group was superior to the LHG group and LHG group. And the difference was statistically significant (P < 0.05) . Conclusion All the proxi- mal tibial nerve muscle branchs can be used to repair the deep peroneal nerve injury, and the soleus nerve branch is the preferred donor nerve. Key words: Nerver transposition; Common peroneal nerve injury; Tibial nerve; Lower extremity nerve function reconstruction; Rats

Guillain–Barre syndrome (GBS) is an acute demyelinating inflammatory polyradiculoneuropathy characterised by rapidly progressing predominantly motor impairment and areflexia. Studies in patients and animals have provided convincing evidence that GBS is caused by an aberrant autoimmune response that damages peripheral nerves [1]. GBS rarely develops in patients who suffer from other autoimmune conditions, such as idiopathic thrombocytopenic purpura (ITP), which suggests a shared immune response [2–11]. Rituximab is a monoclonal antibody particularly efficacious in the treatment of several haematological cancers, which has also been used for the treatment of some autoimmune conditions [12]. Here we report on a patient with ITP who developed a typical GBS after treatment with rituximab. This 86-year-old man, with the antecedents of arterial hypertension, chronic obstructive lung disease and atrial fibrillation, consulted in December, 2008, due to purpuric lesions in the lower limbs. He was diagnosed as ITP. His platelet count was 5,000/mm. He received intravenous immunoglobulins (ivIG) 1 mg/kg/day for 2 days plus a descending treatment with oral prednisone (beginning with 1 mg/kg/day) for 1 month. His platelet count after this treatment was 250,000. In January, 2009, he was admitted again because his blood sample showed 10,000 platelets. He was treated with oral prednisone 1 mg/kg/day for 16 consecutive days. This treatment was stopped due to persistent thrombocytopenia (20,000 platelets). IvIG 1 g/kg/day for 2 days and intravenous rituximab (750 mg once a week for 4 weeks) were administered. His platelet count before the last rituximab dose (27 February 2009) was 121,000. Thirty-nine days after the last dose of rituximab (8 April 2009) he developed an acutely ascending progressive tetraparesis. On admission, two days after the beginning of the clinical picture, symmetric weakness, 4/5 in the upper extremities and 3/5 in lower extremities, and universal arreflexia were found. Plantar responses were flexor. Sensory examination was normal and sphincters were not affected. Platelet count was 192,000/mm. A lumbar tap was performed on admission. Glucose levels were normal, there were no cells and protein concentration was 57 mg/dl. The remaining routine laboratory determinations, including tumor markers and a complete autoimmune profile, were normal. With the presumptive diagnosis of Guillain–Barre syndrome, treatment with ivIG 0.4 g/kg/day for 5 days was given. An electrophysiological study, performed six days after the beginning of the symptoms, disclosed slowing of motor conduction velocities (MCV) in all studied nerves. MCV were markedly delayed (\32 m/s) in peroneal and tibial nerves, and slightly slowed in median and ulnar nerves (46 and 49 m/s, respectively). Motor distal latencies (MDL) were clearly prolonged in tibial and medial nerves and within normal limits in peroneal and ulnar nerves. F waves could not be obtained in right peroneal nerve, right posterior tibial nerve and right median nerve, and were delayed in right ulnar nerve. There was attenuation of distal compound muscle R. Jaso C. Valero Services of Internal Medicine, University Hospital Marques de Valdecilla, Santander, Spain

P-NU003. Estimation of cross-sectional area reference values of nerves in the upper and lower extremities using ultrasonography in the Indian population

A misdiagnosis of multifocal motor neuropathy

Objective: The study aimed to investigate whether sample sizes of F-wave study differed according to different nerves, different F-wave parameters, and amyotrophic lateral sclerosis(ALS) patients or healthy subjects. Methods: The F-waves in the median, ulnar, tibial, and deep peroneal nerves of 55 amyotrophic lateral sclerosis (ALS) patients and 52 healthy subjects were studied to assess the effect of sample size on the accuracy of measurements of the following F-wave parameters: F-wave minimum latency, maximum latency, mean latency, F-wave persistence, F-wave chronodispersion, mean and maximum F-wave amplitude. A hundred stimuli were used in F-wave study. The values obtained from 100 stimuli were considered "true" values and were compared with the corresponding values from smaller samples of 20, 40, 60 and 80 stimuli. F-wave parameters obtained from different sample sizes were compared between the ALS patients and the normal controls. Results: Significant differences were not detected with samples above 60 stimuli for chronodispersion in all four nerves in normal participants. Significant differences were not detected with samples above 40 stimuli for maximum F-wave amplitude in median, ulnar and tibial nerves in normal participants. When comparing ALS patients and normal controls, significant differences were detected in the maximum (median nerve, Z=-3.560, P<0.01; ulnar nerve, t=5.019, P<0.01; tibial nerve, Z=-2.475, P<0.05; peroneal nerve, Z=-2.088, P<0.05)and mean F-wave latency (median nerve, Z=-3.243, P<0.01; ulnar nerve, t=3.876, P<0.01; tibial nerve, Z=-2.206, P<0.05; peroneal nerve, Z=-2.205, P<0.05)in all four nerves, F-wave chronodispersion (Z=-3.152, P<0.01)in the ulnar nerve, F-wave persistence in the median (Z=6.139, P<0.01)and ulnar nerves(Z=5.350, P<0.01), mean F-wave amplitude in the tibial nerve(t=2.981, P<0.01), maximum F-wave amplitude in the ulnar (Z=-2.134, P<0.05)and tibial nerves (t=2.746, P<0.01)with 20 stimuli; for chronodispersion in tibial nerve (t=2.551, P<0.05)100 stimuli, for chronodispersion in peroneal nerve (Z=-2.086, P<0.05)80 stimuli, for F-wave persistence in tibial nerve (Z=2.119, P<0.05) 60 stimuli, for mean F-wave amplitude in ulnar (Z=-2.552, P<0.05)and peroneal nerve (Z=-2.228, P<0.05)40 stimuli, for maximum F-wave amplitude in peroneal nerve (t=2.693, P<0.01)60 stimuli were necessary to detect differences. Conclusions: Sample sizes of F-wave study differed according to different nerves, different F-wave parameters , and ALS patients or healthy subjects.

The sciatic nerve (SN) presented with unusual patterns in which five smaller fibers instead of one or two nerves at the level of the Piriformis muscle. Those five fibers measured 7.5 cm from their origin to where they joined to form the SN. The SN terminated in the popliteal fossa by giving rise to three terminal branches: the tibial nerve, the common peroneal nerve, and another unusual nerve that supplied the medial head of the gastrocnemius. This case is unusual because the SN presents with different positional variations of its two components in relation to the piriformis muscle but not five fibers; in addition, the SN normally bifurcates instead of trifurcating when it reaches in the popliteal fossa. The case presented a Type A pattern of SN to the piriformis muscle. This type of pattern has been documented to be the most common in some parts of Africa. Some authors have reported two patterns of trifurcation of the SN. One is a pattern where the SN gave rise to the tibial, superficial, and deep peroneal nerves at the popliteal fossa, and another is a trifurcation pattern where it gave rise to the tibial, common peroneal, and sural nerves. The case is different as it presents an unusual unreported pattern where the SN trifurcates by giving rise to the tibial, common peroneal, and nerve that supplies the medial head of the gastrocnemius muscle. The current variation has never been reported elsewhere.

Tibial and Common Fibular Nerve Block in the Popliteal Fossa with Single Puncture Using Percutaneous Nerve Stimulator: Anatomical Considerations and Ultrasound Description