The medial cord to musculocutaneous (MCMc) nerve transfer: a new method to reanimate elbow flexion after C5-C6-C7-(C8) avulsive injuries of the brachial plexus--technique and results.

The aim of this paper is to report on our ample experience with the medial cord to musculocutaneous (MCMc) nerve transfer. The MCMc technique is a new type of neurotization which is able to reanimate the elbow flexion in multilevel avulsive injuries of the brachial plexus provided that at least the T1 root is intact. A series of 180 consecutive patients, divided into four classes according to the quality of hand function, is available for a long-term follow-up after brachial plexus surgery. The patients enrolled for the study have in common a brachial plexus palsy showing multiple cervical root avulsive injuries at two (C5-C6), three (C5-C6-C7) and four (C5-C6-C7-C8) levels. The reinnervation of the musculocutaneous nerve is obtained via an end-to-end transfer from two donor fascicles located in the medial cord. The selected fascicles are those directed principally to the flexor carpi radialis, ulnaris and, to a lesser degree, the flexor digitorum profundus. Under normal anatomic conditions, they are located in the medial cord, and their site corresponds to the inverted V-shaped bifurcation between the internal contribution of the median nerve and the ulnar nerve. The technique has no failure and no complications when the hand shows a normal wrist and finger flexion and a normal intrinsic function. In case of suboptimal conditions of the hand, the technique has proved technically more challenging, but still with 67% satisfactory results. In the four-root avulsive injuries, however, this method shows its limitations and an alternative strategy should be preferred when possible. EMG analysis shows a reinnervation in both the biceps and the brachialis muscles, explaining the high quality of the observed results. Moreover, this technique theoretically offers the possibility of a "second attempt" at a more distal level in case of failure of the first surgery. This procedure is quick, safe, extremely effective and easily feasible by an experienced plexus surgeon. The ideal candidate is a patient harbouring a C5-C6 avulsive injury of the upper brachial plexus with a normally functioning hand.

Chronic total coronary occlusion in patients with intermediate viability: value of low-dose dobutamine and contrast-enhanced 3-T MRI in predicting functional recovery in patients undergoing percutaneous revascularisation with drug-eluting stent.

PURPOSE: Myocardial viability was evaluated by magnetic resonance imaging (MRI) in patients with chronic total coronary occlusion (CTO) treated with a drug-eluting stent. Change in left ventricular ejection fraction (LVEF) was analysed. MATERIALS AND METHODS: Twenty-three patients with CTO underwent delayed-enhancement (DE) and low-dose dobutamine MRI (LD). Diastolic wall thickness (DWT), dobutamine-induced systolic wall thickening (SWT) and DE transmural extension were quantitatively assessed in vessel-related segments, calculating the contribution of viable tissue to SWT, expressed as viability index (VI)=[SWTx(100 - DE)]/100. Patients with transmural enhancement were excluded from revascularisation. At 6 months follow-up, patients underwent coronary angiography (CA) and MRI. Functional recovery was defined as a 2-mm increase in SWT. RESULTS: Transmural enhancement (mean DE 62.88+/-37.18] was present in three patients. Mean DWT, SWT, VI and DE of recanalised patients were 8.03+/-2.35, 2.64+/-1.56, 1.77+/-1.48 mm and 41.97+/-30.32. Revascularisation was successful in 14/16. Follow-up CA showed patency of treated vessels. Functional recovery was achieved in 13 patients. Functional recovery showed significant correlation with SWT (beta 1,779, p=0.015), and even higher correlation with VI (beta 2.032, p=0.011). LVEF improved significantly [Delta 95% confidence interval (CI) -4.47, p=0.0203). CONCLUSIONS: Invasive CTO treatment has beneficial effects on myocardial contractility that can be predicted by VI, and on LVEF.

3-Tesla MRI for the evaluation of myocardial viability: a comparative study with 1.5-Tesla MRI.

PURPOSE: We compared 3-Tesla (3-T) and 1.5-Tesla (1.5-T) cardiac magnetic resonance imaging (MRI) for the assessment of myocardial viability in nearly identical experimental conditions. MATERIALS AND METHODS: Thirty-five patients (mean age 63+/-11; 94.2% men) submitted to primary coronary angioplasty underwent both 3-T and 1.5-T cardiac MRI, which was considered the gold standard. Comparison was performed on the basis of the same viability imaging protocol, which included resting cine-MR [balanced fast-field echo (B-FFE) sequence] followed by contrast-enhanced MR to evaluate perfusion and delayed enhancement (DE). We then performed functional index measurements and visual estimation of kinesis, perfusion and DE referring to a 5-point scale. Image quality was assessed on the basis of signal to noise ratio (SNR) and contrast to noise ratio (CNR). RESULTS: We found nonsignificant differences between the two scanners (P=NS) in measuring the functional and viability parameters. Myocardial SNR was significantly higher with 3-T MRI compared with 1.5-T MRI (61.3% gain). Even though a loss of CNR was recorded in B-FFE and in first-pass perfusion sequences (12.4% and 23.7%, respectively), on DE images, we quantified the increase of SNR and CNR of infarction of 387.8% and 330%, respectively. CONCLUSIONS: We found that 3-T MRI showed high concordance with 1.5-T MRI in the evaluation of functional and viability parameters and provided better evidence of damaged myocardium.

How to quantify infarct size on delayed-enhancement MR images: a comparison between visual and quantitative approach.

PURPOSE: Our aim was to evaluate the reliability of visual quantification of infarct extent on delayed enhanced magnetic resonance images. MATERIALS AND METHODS: Eighty patients with previous myocardial infarction underwent cine and contrast-enhanced cardiac magnetic resonance imaging. The gadolinium-enhanced images were evaluated using a segmental model with two different methods: a visual score on a 5-point scale (0 no hyperenhancement, 4 hyperenhancement>76% of myocardial wall) and a quantitative analysis based on the manual tracing of infarct contours with automatic threshold analysis. Each segment was also assigned a wall-motion score ranging from 0 (normokinesia) to 4 (dyskinesia). Statistical evaluation was performed. RESULTS: Out of 1,280 segments, 322 (25.1%) showed wall-motion abnormalities with enhancement in 327 (25.5%) evaluated with visual score and in 414 (32.3%) quantitatively. Among segments with normal or mild hypokinesia, 89.2% had a delayed-enhancement scoreor=3. Mean time required for the visual and quantitative approach was 7+/-3 and 18+/-9 min, respectively. There was strong agreement between the visual and quantitative method (k=0.92; p<0.01). CONCLUSIONS: Visual analysis of delayed enhancement is a timesaving approach that is sufficient to assess the transmural extent of infarction. Moreover, it has high correlation with wall-motion abnormalities.

Transarticular repair of the brachial plexus. Case report.

This paper illustrates the repair of a complex and unusually placed iatrogenic injury of the brachial plexus. The authors present the case of a 36-year old woman, musician (piano solista), with a dumbbell tumour of the brachial plexus. A general surgeon performed a gross total removal of the tumour, cutting it flush with the exit of the neuroforamen and this resulted in a severe upper brachial plexus injury. Four months later, the brachial plexus was repaired with a nerve graft, using a double extraforaminal and preforaminal approach via the transarticular route. The surgical procedure proved to be effective and without significant consequences for the patient.

Surgical treatment of common peroneal nerve injuries: indications and results. A series of 62 cases.

AIM: Common peroneal nerve (CPN) injuries represent the most common nerve lesions of the lower limb and can be due to several causative mechanisms. Although in most cases they recover spontaneously, an irreversible damage of the nerve is also likely to occur. Nerve regeneration following CPN repair is poorer if compared to other peripheral nerves and this can explain the reluctant attitude of many physicians towards the surgical treatment of these patients. Among the several factors advocated to explain the poor outcome following surgery, it has been suggested that reinnervation might be obstacled by the force imbalance between the functioning flexors and the paralysed extensors that eventually results in the fixed equinism of the foot, due to the excessive contracture of the active muscles and the shortening of the heel cord. Therefore the early correction of these forces might favour nerve regeneration. Following such hypothesis, the authors treat irreversible CPN injuries performing a one-stage procedure of nerve repair and tibialis tendon transfer. We report our experience, describing the indications to surgical treatment, the operative technique and the postoperative clinical outcome correlated with the causative mechanisms of the injuries. METHODS: A 62-patient series controlled over a period of 15 years with a post-traumatic palsy of the CPN is reported. All the patients underwent surgery. In open wounds, when a nerve transection was suspected, surgery was performed at emergency (2 cases). In closed injuries, operative treatment was advised when no spontaneous regeneration occurred 3-4 months after the injury. From 1988 till 1991, 9 patients were elected for surgery : in 6 cases treatment consisted of neuroma resection and nerve repair by means of a graft. In 3 patients it was performed only a CPN decompression at the fibular neck. Since 1991, surgical treatment has always consisted of nerve repair associated with a tendon transfer during the same procedure. Fifty-three patients were elected for surgery. Nerve repair was achieved by direct suture in 1 case and by means of a graft in 46 patients. Decompression of the CPN at the fibular neck was performed in 6 patients where nerve continuity was demonstrated. RESULTS: In the first group of patients, nerve repair outcome was highly disapponting: no recovery in 5 cases, reinnervation occurred in 1 patient only (M1-2). CPN decompression was followed by complete recovery in 2 cases, no improvement was observed in 1 case. Nerve repair associated with tibialis tendon transfer dramatically improved the postoperative outcome: at 2 year follow-up, neural regeneration was demonstrated in 90% of the patients. Surgical outcome depends on the causative mechanisms of the lesion: sharp injuries and severe dislocations of the knee had an excellent recovery, while in crush injuries and gunshot wounds good recovery was less common. CONCLUSION: Surgical treatment of CPN injuries can nowadays be highly rewarding. CPN palsies in open wounds should undergo surgical exploration at emergency. In close injuries with no spontaneous recovery within 4 months after the injury, patients should be advised to seek surgical treatment regardless the causative mechanism of the lesion. According to our experience, the association of a transfer procedure to nerve repair enhances neural regeneration, dramatically improving the surgical outcome of these injuries.

Common peroneal nerve injuries in knee dislocations: results with one-stage nerve repair and tibialis posterior tendon transfer.

We report our experience in the treatment of common peroneal nerve (CPN) palsy following knee dislocations: a twelve-year surgical series of 26 patients presenting with a traumatic injury of the lateral sciatic nerve and no spontaneous recovery is reviewed. From 1988 to 1991, we performed nerve surgery alone on 3 patients. Their results were highly disappointing and in none did we observe muscle recovery. Since 1991 nerve surgery was associated with a palliative procedure for 23 patients. Although at surgical exploration, severe nerve damage was found in 87% of these patients (thereby indicating the need for graft repair), the overall outcome was good, with a score of M3 on the BMRC scale in about 75% of the cases. These results suggest that the one-stage association of microsurgical nerve repair and tibialis posterior tendon transfer changed the destiny of these injuries.

Aggressive fibromatosis (desmoid tumor) of the radial nerve: favorable resolution. Case report.

Aggressive fibromatosis (desmoid tumor) of a peripheral nerve is a rarity. Isolated cases have been reported in which the tumor originated from neighboring structures and only secondarily invaded the nerves. The case described in this report is unusual because the tumor selectively invaded the patient's nerve fascicles, requiring removal and graft repair. The procedure was followed by an excellent clinical recovery and no recurrence as of the 6-year follow-up review.

Three-dimensional MR myelography of traumatic injuries of the brachial plexus.

PURPOSE: To determine the diagnostic accuracy of three-dimensional MR myelography in the evaluation of traumatic injuries of the brachial plexus. METHODS: Twenty patients with clinical and electromyographic evidence of traumatic brachial plexopathy were examined with three-dimensional MR myelography, conventional cervical myelography, and CT myelography 1 to 9 months after trauma. Three-dimensional MR myelography was performed on a 1.5-T MR unit with a constructive interference in steady state (CISS) technique. For each patient, maximum intensity myelographic projections and multiplanar reconstruction reformatted 1-mm axial sections were obtained from the same 3-D data set. Three-dimensional MR myelographic findings were compared with findings at cervical myelography and CT myelography. Surgical findings were available for comparison in 13 patients. RESULTS: Three-dimensional MR myelography enabled detection of meningoceles with avulsed or intact nerve roots, partial or complete radicular avulsions without disruption of the thecal sac, dural sleeve abnormalities, and dural scars. Assuming cervical myelography and CT myelography as the standards of reference, 3-D MR myelography showed 89% sensitivity, 95% specificity, and 92% diagnostic accuracy in the evaluation of nerve root integrity. CONCLUSION: Three-dimensional MR myelography can show the majority of traumatic lesions that involve the proximal portion of the brachial plexus in a single rapid examination. On the basis of our findings, we propose this technique as a screening examination for patients with traumatic brachial plexus palsy.

Toward a transgenic mouse model of remyelination.

The molecular mechanisms necessary for remyelination by oligodendrocytes remain unexplored. We previously characterized a myelin basic protein promoter-lacZ (MBP-lacZ) transgene whose expression is regulated uniquely during development, and also in pathological situations, suggesting that it may be a useful reporter of molecular mechanisms during remyelination. As a first step toward creating a transgenic mouse model of remyelination, we cultured oligodendrocytes from these transgenic mice and showed that expression of MBP-lacZ appeared in parallel with a marker of oligodendrocyte maturation, galactocerebroside (GC). In addition, basic fibroblast growth factor blocked the expression of both MBP-lacZ and GC in these cells. Therefore, expression of MBP-lacZ reflects not only the developmental stage of oligodendrocytes, but also extrinsic influences on oligodendrocytes. These data suggest that MBP-lacZ may be a useful marker in transgenic mouse models of remyelination.

Brachial plexus injuries. Guidelines for management: our experience.

In spite of the progress made by microneurosurgery, the treatment of brachial plexus injuries still remains a great challenge. This personal series of 49 patients with brachial plexus injuries (excluding tumours and thoracic outlet syndromes) is peculiar because the cases arose after the introduction in Italy of the law requiring all motorcyclists to wear a safety helmet. Our experience confirms that there has been a 32% increase in very severe almost irreparable injuries of the plexus in comparison with previous data reported in the literature. This is probably due to the higher rate of survival among severely-injured patients, although the possibility of a direct effect of the helmet on the plexus cannot be completely discarded. Our results confirm the good prognosis of the microsurgical repair of C5-C6 stretch injuries and infraclavicular lesions.

Superficial siderosis of the central nervous system after brachial plexus injury. Case report.

Superficial siderosis is a rare condition characterized by deposition of hemosiderin in the leptomeninges and in the subpial layers of the brain and spinal cord. It is associated with cerebrospinal fluid abnormalities consistent with recurrent bleeding into the subarachnoid space. The usual symptoms are hearing loss, ataxia, spastic paraparesis, sensory and sphincter deficits, and mental deterioration. A case is presented of severe superficial siderosis of the central nervous system in a 51-year-old man who had suffered a brachial plexus injury at the age of 20 years. The diagnosis was made by means of magnetic resonance imaging 16 years after the initial symptoms, which comprised bilateral hearing loss and anosmia. Subarachnoid bleeding was due to traumatic pseudomeningocele of the brachial plexus, a very unusual cause of superficial siderosis. This case is interesting insofar as the surgical treatment prevented further bleeding and possibly progression of the disease.

Expression of the integrin alpha 6 beta 4 in peripheral nerves: localization in Schwann and perineural cells and different variants of the beta 4 subunit.

Integrin alpha 6 beta 4 is expressed in human peripheral nerves, but not in the central nervous system. This integrin heterodimer has previously been found in perineural fibroblast-like cells and in Schwann cells (SCs), which both assemble a basement membrane but do not form hemidesmosomes. We show here that in SCs, which had formed a myelin sheath, alpha 6 beta 4 was enriched in the proximity of the nucleus, at Ranvier paranodal areas and at Schmitt-Lanterman clefts; alpha 6 beta 4 was also found at the grooved interface between small axons and non-myelinating SCs. Immunoprecipitation of human peripheral nerves, in combination with Western blotting showed that beta 4 is associated with the alpha 6A subunit. Northern blot analysis of human peripheral nerves showed a single beta 4 transcript of 6 kb. Using the reverse transcriptase polymerase chain reaction, we detected two mRNA species, one for the most common (-70, -53) form of beta 4 and the other encoding the (+53) variant of beta 4. Cultured SCs were devoid of alpha 6 beta 4 but expressed alpha 6 beta 1, indicating that SCs lose beta 4 expression when contact with neurons is lost. Thus, resting SCs in contact with axons express alpha 6A in combination with beta 4, irrespective of myelin formation. We suggest that alpha 6 beta 4 expressed in SCs plays a role in peripheral neurogenesis.

Tarsal tunnel syndrome. Report of a case and review of clinical and surgical aspects.

We describe a case of tarsal tunnel syndrome treated surgically. We analyze the principal etiopathogenetic and clinical features of the syndrome together with the surgical anatomy and go on to discuss the main steps in the surgical operation, the results and possible postoperative complications.

Duplicated peritoneal catheter as a cause of shunt malfunction. Case report.

A rare example of ventriculo-peritoneal shunt malfunction is presented. Radiological and operative findings demonstrated a self-duplication with upward migration of the peritoneal catheter.

Cerebromeningeal pleomorphic xanthoastrocytoma. Report on four cases: clinical, radiologic and pathological features. (Including a case with malignant evolution).

Three cases of cerebromeningeal pleomorphic xanthoastrocytoma are presented and the recurrence of a fourth case, previously described in 1980, is examined because of its evolution towards malignancy. Clinical, radiologic and pathological aspects are discussed and the general features of the previously reported cases of xanthoastrocytoma are reviewed.

Reversal of oculomotor disorders after intracranial aneurysm surgery.

Forty-nine patients with oculomotor nerve palsy due to intracranial aneurysm were examined. The reversal of third nerve palsy is related to modality of onset and surgical timing: "early" surgery (within 14 days from the onset of oculomotor palsy) promises a better prognosis for ocular function; recovery starting within the first month will probably be complete. A full recovery is probably seen only with conduction block (neuroapraxia) or minor axonal changes (axonolysis). Clinical features of third nerve palsy due to intracranial aneurysms versus other causes of oculomotor palsy are discussed.

Skull bone defects. Preliminary results using a new prosthesis.

The use of a new prosthetic material (110 DTEX F 33 Propylene and Medical Polyester Torlen 165 DTEX) in the reconstruction of bone defects of the skull, even of large dimension, is described by the authors. The material has good biologic tolerance, is already pre-moulded, can be easily adapted to the exact size of the defect and offers remarkable aesthetic and functional results. EEG, X-ray, MRI and CT can be performed without artefact and interferences.

[Hyponatremia in meningeal hemorrhage]. / L'hyponatremie au cours de l'hémorragie méningée.

One hundred patients affected by S.A.H. have been studied, evaluating the possible correlations between clinical findings and hyponatremia. For a better understanding of hyponatremia during S.A.H., the hematic concentration of A.D.H. and A.N.P. have been determined and correlated with hyponatremia.