Domenico De Grandis

Hemihypoglossal Nerve Transfer in Brachial Plexus Repair: Technique and Results

OBJECTIVE In multiple avulsions of the brachial plexus, the search for extraplexal donor nerves in the hope of achieving motor neurotization is a major goal. We explored the possibility of using the hypoglossal nerve as a transfer point to reanimate muscles in the upper limb. METHODS The hypoglossal nerve was used as a donor nerve for neurotization in seven patients with avulsive injuries of the brachial plexus. The surgical technique—an end-to-side microsuture using approximately half of the nerve fascicles—is basically the same as that used in the hypoglossal nerve-facial nerve jump graft, which is a well-known technique in facial nerve reanimation. The recipient nerves were the suprascapular (two patients), the musculocutaneous (one patient), the posterior division of the upper trunk (two patients), and the medial contribution to the median nerve (two patients). RESULTS In spite of a connection documented by electromyography and selective activation in three of seven patients, the functional results in our patients were extremely disappointing: no patient had an outcome better than M1 in the reinnervated muscles. CONCLUSION This technique was of no help to the patients and thus has been abandoned at our institution.

RELIABILITY OF A NOVEL NEUROSTIMULATION METHOD TO STUDY INVOLUNTARY MUSCLE PHENOMENA

Experimental methods involving painful electrical stimulation of a peripheral nerve showed the existence of a minimum stimulation frequency capable of inducing cramp, termed “threshold frequency” (TF). Our aim was to test an alternative method to induce fasciculations and cramps electrically. Two daily sessions of electrical stimulation of the abductor hallucis muscle were performed in 19 volunteers on 3 days: stimulation trains of 150 monophasic square pulses (duration 152 μs) of increasing frequency (current intensity 30% higher than maximal; frequency of the first trial, 4 pps; recovery between trials, 1 min) were delivered to the main muscle motor point until a cramp developed. Once a cramp was induced the protocol was repeated after 30 min. To verify by electromyography that cramp occurred, a surface electrode array was placed between the motor point and the distal tendon. Ambient and skin temperature were kept constant in all sessions. Fasciculations and cramps were elicited in all subjects. We observed the following median (interquartile range) values of TF: day 1 (session 1), 13 (6) pps; day 1 (session 2), 16 (4) pps; day 2 (session 1), 16 (6) pps; day 2 (session 2), 18 (6) pps; day 3 (session 1), 17 (4) pps; day 3 (session 2), 18 (8) pps. TF intersession intraclass correlation coefficients were 0.82, 0.92, and 0.90 for days 1, 2, and 3, respectively. TF interday intraclass correlation coefficient was 0.85. The absence of pain due to the stimulation and the demonstration of TF reliability support the use of our method for the study of involuntary muscle phenomena. Muscle Nerve, 2007

Polyneuritis cranialis: clinical and electrophysiological findings.

A 13 year old boy, developed bilateral facial weakness, dysphonia and dysphagia acutely after a febrile illness. Neurological examination and MRI of the brain were normal. The CSF protein level increased. Blink reflex monitoring during clinical recovery was consistent with demyelination of the lower cranial nerves innervating the branchial arch musculature, a rare variant of Guillain-Barré syndrome.

Conversion ratio between Dysport and Botox in clinical practice: an overview of available evidence

The optimal conversion ratio between Dysport and Botox—the two botulinum neurotoxin type A products (BoNT-As) supported by the larger bulk of evidence—has been extensively debated, because of its broad medical and economic implications. The article discusses the available evidence on the conversion ratio between Dysport and Botox in adults affected by spasticity, cervical dystonia, blepharospasm and hemifacial spasm, with a focus on clinical trials that specifically addressed this issue. In addition, some suggestions on the conversion ratio between Dysport and Xeomin can be extrapolated, since Xeomin has the same efficacy and safety profile as Botox and is exchangeable with Botox with a 1:1 conversion ratio. Taken together, the findings retrieved from this literature research suggest that a conversion ratio of 3:1 (Dysport:Botox)—or even lower—can be considered appropriate for the treatment of the above-mentioned conditions. Higher conversion ratios may lead to an overdosing of Dysport, with a potential increased incidence of adverse events. Therefore, we recommend that physicians using both products consider using a lower conversion factor as a guide, adjusting it upwards as required based on the specific characteristics and response to treatment of each patient.

Lower-limb lengthening in short stature: An electropysiological and clinical assessment of peripheral nerve function

We assessed peripheral nerve function during and after lower-limb lengthening by callotasis in 14 patients with short stature, using motor conduction studies. Four patients with short stature of varying aetiology showed unilateral and one showed bilateral weakness of foot dorsiflexion. Both clinical and electrophysiological abnormalities consistent with involvement of the peroneal nerve were observed early after starting tibial callotasis. There was some progressive electrophysiological improvement despite continued bone distraction, but two patients with Turners syndrome had incomplete recovery. A greater percentage increase in tibial length did not correspond to a higher rate of peroneal nerve palsy. The function of the posterior leg muscles and the conduction velocity of the posterior tibial nerve were normal throughout the monitoring period. The F-wave response showed a longer latency at the end of the bone distraction than in basal conditions; this is probably related to the slowing of conduction throughout the entire length of the nerve.

SERCA1 protein expression in muscle of patients with Brody disease and Brody syndrome and in cultured human muscle fibers

Brody disease is an inherited myopathy associated with a defective function of sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase 1 (SERCA1) protein. Mutations in the ATP2A1 gene have been reported only in some patients. Therefore it has been proposed to distinguish patients with ATP2A1 mutations, Brody disease (BD), from patients without mutations, Brody syndrome (BS). We performed a detailed study of SERCA1 protein expression in muscle of patients with BD and BS, and evaluated the alternative splicing of SERCA1 in primary cultures of normal human muscle and in infant muscle. SERCA1 reactivity was observed in type 2 muscle fibers of patients with and without ATP2A1 mutations and staining intensity was similar in patients and controls. Immunoblot analysis showed a significant reduction of SERCA1 band in muscle of BD patients. In addition we demonstrated that the wild type and mutated protein exhibits similar solubility properties and that RIPA buffer improves the recovery of the wild type and mutated SERCA1 protein. We found that SERCA1b, the SERCA1 neonatal form, is the main protein isoform expressed in cultured human muscle fibers and infant muscle. Finally, we identified two novel heterozygous mutations within exon 3 of the ATP2A1 gene from a previously described patient with BD.

Carnitine Kinetics during Dialysis

Plasma total and free carnitine concentrations were measured in 14 patients during a 4-hour hemodialysis session at 40-min intervals. Although postdialysis carnitine levels were lower than predialysis

ALS and myasthenia: An unusual association in a patient treated with riluzole.

Treatment with riluzole has been proposed in both sporadic and familial amyotrophic lateral sclerosis (ALS). We report a patient with familial ALS who developed myasthenia gravis (MG) during treatment with riluzole. A 53-year-old man, with a positive family history spanning three generations of autosomal dominant ALS, presented with weakness and atrophy in his right hand, cramping pain in the muscles of both legs, and diffuse fasciculations. The patient complained also of difficulty in walking for long distances and in arising from a chair. Clinical examination revealed hyperreflexia, muscular atrophy, fasciculations, and weakness in the arms and legs. Sensory abnormalities were not present. Needle electromyography showed fibrillation potentials, positive sharp waves, fasciculations, and increased number of polyphasic and long-duration motor unit potentials in right tibialis anterior and vastus medialis muscles. Recruitment showed a poor interference pattern, with motor unit potentials firing rapidly. Motor conduction studies in the right and left median, ulnar, radial, and peroneal nerves were normal, as were sensory studies of the right and left median, ulnar, and sural nerves. Somatosensory evoked potentials elicited from the right and left median and posterior tibial nerves and recorded over the scalp also were normal. Motor evoked potentials had prolonged central motor conduction time (23 ms and 24 ms in right and left extensor digitorum brevis, respectively; normal value, 19 ms). Cerebrospinal fluid protein and glucose concentration and the cell count were normal. Treatment with riluzole was started, with an initial dose of 100 mg per day. After 3 months, the patient complained of unusual muscle fatigability which was promptly reversed by rest. On examination, the patient showed ptosis and diplopia. Repetitive nerve stimulation (RNS) at 3 Hz showed a decrement exceeding 40% in deltoid and orbicularis oculi muscle. Single-fiber electromyography (SFEMG) showed increased jitter in arms and cranial muscles (in five of 20 pairs of potentials recorded from extensor digitorum communis, biceps, and frontalis muscle, respectively) and blocks (in one of three and in three of five pairs of potentials from extensor digitorum communis and orbicularis oculi, respectively.) Following the intravenous injection of 5 mg edrophonium (Tensilon), ptosis and diplopia improved, and RNS showed a complete (biceps and deltoid) or partial (orbicularis oculi) reversal of decrement. The serum concentration of acetylcholine receptor (AChR) antibodies was increased (22.5 pmol/L in August 1996; normal values, <0.4 pmol/L). Computed tomographic scan of the thorax was normal. Pyridostigmine bromide (Mestinon) was started at the same time riluzole was stopped, with clinical improvement, chiefly in the cranial muscles. A second SFEMG showed shortening of abnormal jitter and a decreased incidence of blocking. The serum concentration of AChR antibodies gradually decreased (4 pmol/mL in February 1997; 2.2 pmol/mL in July 1998). In patients with ALS, electrophysiological studies often show signs of defective neuromuscular transmission (decrementing response to RNS, abnormal jitter, and an increased incidence of blocking), and a Tensilon test may be positive. However, in our patient, the clinical (particularly ocular muscle involvement) and neurophysiological findings as well as the clear improvement after treatment with anticholinesterase drugs suggest a diagnosis of MG in addition to the presence of established ALS. To our knowledge, a possible association between ALS and MG is very unusual. Noseworthy et al. described a patient whose presentation suggested MG but who subsequently developed tongue fasciculations and whose lack of response to treatment led to a diagnosis of ALS. Recently, Okuyama et al. described an ALS patient with increased AChR antibody (0.50 nmol/L), but clinical features of MG were not present and the presence of the AChR antibody may simply have been a coincidental finding without any pathoCCC 0148-639X/00/020294-03

Novel transthyretin missense mutation (Thr34) in an Italian family with hereditary amyloidosis

We report on the genetic and molecular characterisation of an Italian family with a late-onset, autosomal dominant transthyretin amyloidosis. The transthyretin gene was analysed by polymerase chain reaction (PCR), restriction generating PCR, and sequencing, allowing us to discover in one allele a novel point mutation. It consists of a G to C transversion at position 1692 of the genomic sequence, leading to a Thr for Arg substitution at the position 34 of the polypeptidic chain. This mutation is associated with a severe sensory-motor peripheral neuropathy and a restrictive cardiomyopathy.

Spinal somatosensory evoked potentials in patients with tethered cord syndrome.

We studied the electrophysiological changes occurring in six patients with tethered cord syndrome. Evidence of spinal malformations was provided by magnetic resonance imaging. The functional assessment of the spinal cord was performed by analysing both spinal and cortical somatosensory evoked potentials. The evoked electrospinogram was recorded from the thoracic and lumbosacral spinous processes. The N22 lumbosacral potential was selectively affected, being rostrocaudally displaced and reduced in amplitude or even absent in patients with neurological signs indicating a segmental lower cord lesion. Inter-peak somatosensory evoked potentials latency was normal in all cases, suggesting that ascending axonal potentials in the dorsal column fibres may be synchronized. Segmental potentials of the lumbosacral response, originating from the post-synaptic activity of dorsal horn interneurons, are selectively affected in this syndrome resulting from the rostrocaudal displacement of the spinal cord due to tethering. Our findings in the clinical field are consistent with previous experimental evidence indicating a different sensitivity of the gray vs. white matter to progressive stretching.