A Review of Recent Advances in Ultrasound, Placed in the Context of Pain Diagnosis and Treatment.

Ultrasound plays a significant role in the diagnosis and treatment of pain, with significant literature reaching back many years, especially with regard to diagnostic ultrasound and its use for guiding needle-based delivery of drugs. Advances in ultrasound over at least the last decade have opened up new areas of inquiry and potential clinical efficacy in the context of pain diagnosis and treatment. Here we offer an overview of the recent literature associated with ultrasound and pain in order to highlight some promising frontiers at the intersection of these two subjects. We focus first on peripheral application of ultrasound, for which there is a relatively rich, though still young, literature. We then move to central application of ultrasound, for which there is little literature but much promise.

Percutaneous Image-Guided Cryoablation for the Treatment of Phantom Limb Pain in Amputees: A Pilot Study.

PURPOSE: To prospectively evaluate percutaneous image-guided nerve cryoablation for treatment of refractory phantom limb pain (PLP) in a pilot cohort for purposes of deriving parameters to design a larger, randomized, parallel-armed, controlled trial. MATERIALS AND METHODS: From January 2015 to January 2016, 21 patients with refractory PLP underwent image-guided percutaneous cryoneurolysis procedures. Visual analog scale scores were documented at baseline and 7, 45, and 180 days after the procedure. Responses to a modified Roland Morris Disability Questionnaire were documented at baseline and 7 and 45 days after the procedure. RESULTS: Technical success rate of the procedures was 100%. There were 6 (29%) minor procedure-related complications. Disability scores decreased from a baseline mean of 11.3 to 3.3 at 45-day follow-up (95% confidence interval 5.8, 10.3; P < .0001). Pain intensity scores decreased from a baseline mean of 6.2 to 2.0 at long-term follow-up (95% confidence interval 2.8, 5.6; P < .0001). CONCLUSIONS: Image-guided percutaneous nerve cryoablation is feasible and safe and may represent a new efficacious therapeutic option for patients with phantom pains related to limb loss.

Acute combined exposure to heavy metals (Zn, Cd) blocks memory formation in a freshwater snail.

The effect of heavy metals on species survival is well documented; however, sublethal effects on behaviour and physiology are receiving growing attention. Measurements of changes in activity and respiration are more sensitive to pollutants, and therefore a better early indicator of potentially harmful ecological impacts. We assessed the effect of acute exposure (48 h) to two heavy metals at concentrations below those allowable in municipal drinking water (Zn: 1,100 µg/l; Cd: 3 µg/l) on locomotion and respiration using the freshwater snail, Lymnaea stagnalis. In addition we used a novel assessment method, testing the ability of the snail to form memory in the presence of heavy metals in both intact snails, and also snails that had the osphradial nerve severed which connects a chemosensory organ, the osphradium, to the central nervous system. Aerial respiration and locomotion remained unchanged by acute exposure to heavy metals. There was also no effect on memory formation of these metals when administered alone. However, when snails were exposed to these metals in combination memory formation was blocked. Severing the osphradial nerve prevented the memory blocking effect of Zn and Cd, indicating that the snails are sensing these metals in their environment via the osphradium and responding to them as a stressor. Therefore, assessing the ability of this species to form memory is a more sensitive measure of heavy metal pollution than measures of activity, and indicates that the snails' ability to demonstrate behavioural plasticity may be compromised by the presence of these pollutants.

Diffusion-Weighted Magnetic Resonance Imaging Improves the Accuracy of Differentiation of Benign from Malignant Peripheral Nerve Sheath Tumors.

OBJECTIVE: In patients with neurofibromatosis type 1 (NF1), it is important to accurately determine when plexiform neurofibroma (pNF) transforms to a malignant peripheral nerve sheath tumor (MPNST). The purpose of this study is to investigate the usefulness of diffusion-weighted imaging (DWI) in differentiating pNF and MPNST in NF1 patients. METHODS: Among the NF1 patients who were referred to our hospital between 1985 and 2015, 10 cases of MPNST and 19 cases of pNF were included. We evaluated features of standard magnetic resonance imaging according to the differentiation criteria of malignancy from benignancy as previously reported, apparent diffusion coefficient (ADC) value based on the DWI and the correlation between ADC value and benignancy/malignancy. ROC analysis was performed to determine the appropriate cutoff value of ADC. RESULTS: There were significant differences between MPNST and pNF in the size of the tumor (P = 0.009), peripheral enhancement pattern (P = 0.002), perilesional edema-like zone (P = 0.0008), and intratumoral cystic change (P = 0.02). The mean and minimum values of ADC were significantly lower in MPNST than those in pNF (P = 0.03 and P = 0.003, respectively). When we set a cutoff value of mean ADC as 1.85 × 10-3 mm2/s, the sensitivity and specificity were 80% and 74%, respectively. The area under the curve value improved by adding the Wasa score to the mean ADC evaluation. CONCLUSIONS: ADC values determined by DWI are useful in differentiating MPNST from pNF and adding ADC evaluation to standard MRI evaluation improved the diagnostic accuracy.

Functional outcomes of Gartland III supracondylar humerus fractures with early neurovascular complications in children: A retrospective observational study.

This was a retrospective observational study. The aim of this study was to evaluate functional outcomes in children treated for Gartland III supracondylar humerus (SCH) fracture with neurovascular (NV) injuries using validated outcome measures. A secondary goal was to determine whether clinical parameters such as age at injury, sex, weight, fracture site, and/or direction of displacement could predict NV injury at the time of fracture or long-term functional outcomes in these patients.One hundred fifty-four patients of Gartland III SCH fractures between March 2004 and May 2013 were studied retrospectively. The patients were divided into 2 groups according to the presence of NV injury. Medical records and radiographs were reviewed to assess several parameters, including age, sex, weight, treatment intervention, the extremity involved, direction of fracture displacement, and NV injury. Functional outcome was assessed on final follow-up using the Pediatric Outcomes Data Collection Instrument (PODCI) and Quick Disabilities of the Arm, Shoulder, and Hand (Quick DASH) outcome measures. Statistical analysis was used to determine the relationship between NV injury and functional outcomes.There were 33 cases with Gartland III SCH fracture associated with NV injuries (10 cases of vascular compromise, 14 cases of neural injury, and 9 cases involving both vascular compromise and neural injury). There were significant differences between the 2 groups in age (P  =  .048), weight (P  =  .009), and direction of displacement (P  =  .004). Vascular compromise and median nerve injury were most common in fractures with posterolateral displacement, and radial nerve injuries were common in fractures with posteromedial displacement. The mean global function score in the PODCI was 91.4 points, and the mean Quick DASH score was 11.7 points, with excellent functional outcomes. No differences in outcomes were identified based upon age, fracture site, sex, weight, direction of displacement, or operative technique in NV injury patients (P > .05).The majority of patients with Gartland III SCH fractures associated with NV injuries returned to a high functioning level after treatment of their injuries. NV injury does not appear to influence functional outcomes. Good functional results can be expected regardless of age, fracture site, sex, weight, direction of displacement, and operative technique.

Video-gait analysis of functional recovery of nerve repaired with chitosan nerve guides.

Quantitative analysis of peripheral nerve regeneration using nerve guides is commonly evaluated through histomorphometry and walking track analysis. We conducted a unique assessment of functional sciatic nerve recovery treated with chitosan nerve guides. We used video-gait analysis to evaluate the extent of functional nerve recovery by measuring the ankle angle at different gait cycle phases. We also correlated the gastrocnemius muscle weight measurements and histological analysis to functional nerve recovery. The chitosan group showed increased functional improvement compared to the control groups at the end of a 12-week period ( p < 0.05). Although both control and chitosan angle measurements were lower than those recorded for presurgery animals, the angle measurements significantly improved over the 12-week period. Stance phase duration of the gait cycle was also recorded, which showed a significant increase over the 12-week time period. The muscle weight parameter indicated a significant decrease in muscle atrophy and restoration of functional strength. Histological analysis revealed that the chitosan nerve guide provided significantly increased axonal growth. The functional results indicated that chitosan nerve guides enhanced functional improvement over no repair processes.

[Microsurgery in reanimation, lymphoedema and hand surgery].

Microsurgery is defined as surgery performed with the aid of ocular magnification. In Denmark, this is undertaken by four units. This review describes the history of microsurgery which evolved during the 1960s. Microsurgery in hand surgery is primarily replantation and revascularisation but also peripheral nerve surgery as well as brachial plexus surgery. Lymphoedema is being treated with super microsurgery on an experimental basis. Dynamic reconstruction of facial palsy is performed in a two-stage operation with cross-over nerve graft and a free microvascular muscle flap, typically gracilis.

Chronic pain states: invasive procedures.

OBJECTIVE: To provide a review of chronic pain states, focusing on neuroanatomic pathways and their influence on treatment strategies (part 2 of a two-part series). DATA SOURCE: A thorough literature review of published articles available in Medline from 1966 to 1996 on the topic of pain management, including diagnosis, pathophysiology, interventions, and treatment. CONCLUSIONS: Understanding the pathophysiology of chronic pain and the role of chemical mediators, such as enkephalins, norepinephrine, serotonin, and substance P, may improve pain management. As a result, pain control measures can target inhibition of the descending pain modulation pathways of the spinal cord, in addition to the peripheral or central actions of traditional analgesics. Fewer ablative surgical interventions are performed for pain control, because they often provide only temporary relief at the expense of significant permanent neurological deficits. However, there are more augmentative procedures now available for the patient with intractable and unresponsive pain, although referral to specialized pain clinics may benefit particularly difficult cases.

Peripheral nerve repair using a poly(organo)phosphazene tubular prosthesis.

Nerve regeneration experiments were carried out using tubular nerve guides of poly[(ethylalanato)1.4(imidazolyl)0.6phosphazene] (PEIP). By means of in vivo tests, this polymer was found to be biodegradable and transformed into harmless products. The tubular nerve guides were prepared by deposition of the dissolved polymer on a glass capillary tube, followed by evaporation of the solvent (methylene dichloride). After transectioning, rat sciatic nerve stumps were immediately sutured into the ends of 10-mm-long polymer tubes. On removal of the prosthesis, after implantation for 45 d, a tissue cable was found bridging the nerve stumps in all cases. Histological analysis revealed that the tissue cable was essentially composed of a regenerated nerve fibre bundle. A parallel series of experiments was undertaken to compare the use of silicone tubes that are not biodegradable and are most frequently used for studies of nerve regeneration with tubulization techniques. The advantages of biodegradable PEIP tubular nerve guides used for peripheral nerve repair are discussed.

In vitro pre-degenerated nerve autografts support CNS axonal regeneration.

In the present study we compared, in adult rats, the axonal regeneration of central respiratory neurons within autologous fresh (f-; grafted immediately after removal) and pre-degenerated (pd-; grafted after being stored during 3 days in saline at +8 degrees C) peripheral nerve grafts (PNGs) implanted within the C2 cervical spinal cord. The proximal end of the left peroneal nerve was implanted in the site of projection of medullary respiratory neurons (ventro-lateral quadrant) and the distal part of each nerve graft was left unconnected (blind-ended graft). PNGs were examined 2 to 4 months after grafting. Central neurons regenerating axons within the PNGs were studied by recording spontaneous unit activity from small strands teased from the grafts. In control f-PNGs (n = 9), 248 filaments had spontaneous activities, 58 of these were respiratory-related, i.e. had discharge patterns identical to those of normal respiratory (inspiratory and expiratory) neurons. The presence of regenerated nerve fibers with spontaneous unitary impulse traffic (n = 216) was found in all pd-PNGs (n = 5). Thirty-four had respiratory patterns identical to those found within f-PNGs and corresponded to efferent activity. No statistically significant differences in axonal regrowth were found between f- and pd-PNGs. In conclusion, f- and pd-PNGs were equally capable of promoting axonal regeneration of central neurons. The neural components (Schwann cells and others) required for axonal regeneration of adult central neurons are still effective following 3 days of in vitro peripheral nerve degeneration without special storage conditions (oxygenation, medium inducing ATP synthesis). These results have clinical implications for nerve graft surgery when time is required for typing the tissues of both donor and recipient (post-mortem allografts) or transportation of graft material.

Selective peripheral denervation for spasmodic torticollis: is the outcome predictable?

If botulinum toxin fails in the treatment of cervical dystonia, selective peripheral denervation is now accepted as the best surgical option. Despite the very promising results, however, there is still a substantial group of patients who do not benefit from this procedure. Positive response to prior botulinum toxin therapy seems to be a very good predictor of outcome after selective peripheral denervation (P < 0.01). The meaning of the histological findings of the resected nerves is uncertain. Patients with histologically proven pathological nerves do not seem to benefit more than patients with histological normal ones (P < 0.30).

Birthday of peripheral nervous system surgery: the contribution of Gabriele Ferrara (1543-1627).

SURGERY OF THE peripheral nerves has only recently achieved brilliant results thanks to technological advances in the development of neurosurgical instrumentation. In past centuries, few surgeons made relevant contributions to this topic and improvement was slow and difficult. Avicenna, Guglielmo da Saliceto, and Guido Lanfranchi reported some attempts to suture nerves directly, but Gabriele Ferrara was the first to give a lucid and succinct description of suturing of the stumps of a transected nerve. He described applying gentle traction on the retracted stumps, suturing using a special needle with an eye, after immersion in a decoction of red wine, rosemary, and roses (alcoholic disinfection?), and, finally, insulating the sutured segment with a mixture of oils. We are celebrating the 400th anniversary of the first edition of his fundamental work (1596-1996), and we truly esteem this surgeon, a pioneer of peripheral nerve surgery wo primarily contributed to its progress.

Surgical management of endometriosis-associated pain.

General surgical guidelines are reasonable, but treatment frequently must be individualized. Laparoscopic coagulation can be used for many cases of superficial endometriosis. Resection seems to be associated with an increased resolution of endometriosis. Resection increases the difficulty of the procedure, the time of the operation, and the cost, however. When endometriosis is found coincidentally, it may need no treatment because many women have endometriosis as a self-limited disease. Distinguishing patients who need no treatment from patients who need intermediate or extensive treatment can be difficult. Care is needed to attempt to ensure that patients are neither overtreated nor undertreated.

Bilateral transnasal vidian neurectomy in the management of chronic rhinitis.

Bilateral transnasal vidian neurectomy was performed on 276 patients between 1983 and 1991. The indications for operation were intractable vasomotor rhinitis, resistant allergic rhinitis and recurrent nasal polyposis. Two hundred and fifty-eight patients were contacted and long-term results showed that 88 per cent of the patients had an excellent result.

Neuromas and gaps of sensory nerves of the hand: management using vein conduits.

This study analyzed the efficacy of an interposed vein conduit graft in eliminating symptoms of painful neuroma of sensory nerves of the hand and preventing recurrence after excising the pathologic tissue and bridging the concomitant gap with the distal nerve segment. Twenty-three patients underwent reconstruction of 25 palmar sensory nerve gaps ranging from 12 mm to 28 mm, as well as 2 dorsal gaps of 32 mm and 35 mm, respectively. Eighteen patients had symptomatic painful neuromas. Subjective and objective evaluation criteria were employed for assessment and were compared with data obtained from primary direct suturing in 25 digital nerves of 21 patients. Electrophysiologic measurements, including sensory nerve action potential and conduction velocity, were similar, with both groups having values significantly lower than normal control values. Two-point discrimination measurements were slightly inferior for the vein conduit-reconstructed nerves compared with results attained after direct suturing. However, neuroma symptoms were eliminated, and in combination with the return of adequate sensibility, all but 1 patient resumed full hand function.

Upper extremity nerve lesions (diagnosis, indications, surgical techniques).

OBJECTIVE: Revision and questioning of orthodox principles regarding the conduction of nerve impulse. DESIGN: Retrospective study with clinical analysis of results. SITE: Hospital das Clinicas (HCFMSP), public university institution with research programs and tertiary attention to health. GROUP MEMBERS: Author and a team of residents and trainees. OPERATION: Direct suture of nervous stumps utilizing auxiliary technical procedures:- joint-flexion, nerve transposition, tendon transplants, bone shortening. MEASUREMENT: Clinical evaluation and objective tests for tactile and stereognostic function recovery (Weber Test). RESULTS: Variable, depending on preoperative conditions:- type of lesion, time elapsed since injury. CONCLUSIONS: Neurorrhaphy should be the procedure of choice even for long term lesions, although the expected results may be less favourable. Periodical evaluation from 24 hs. postoperative, checking for early undefined signals of nervous function recovery. Association of specific drugs for chemical biophysics of the nerve.

[Polymer biomaterials (polyphosphazenes) in the repair of peripheral nervous system]. / Biomateriali polimerici (polifosfazeni) nella ricostruzione del sistema nervoso periferico.

Biodegradable polymers gives interesting perspectives of use in making artificial conduits for peripheral nerve reconstruction. Poliphosphazenes are materials highly biocompatible and have a controllable reabsorption rate. According to the substitutes that are introduced in the molecule, they can also be used as a framework for drug release. Conduits obtained with poli [bis(etilalanate) phosphazene] were evaluated as guides for nerve regeneration in an experimental animal model. In six Wistar rats, under general anesthesia and with microsurgical technique, the ischiatic nerve was isolated. On the right side a segment of the nerve was removed in order to create a 10 mm gap. The defect was then repaired using the conduit. On the controlateral limb the nerve continuity was restored using as an autograft the segment removed from the right. Control were performed at 30, 90, 180 days and consisted in histological and electron microscopy investigations. They showed the gradual degradation of the conduit without signs of local and general toxicity. The regeneration of the nerve fibers in the lumen of the conduit was not significantly different from the one obtained with the autologous grafts. So poliphosphazene conduits may be considered effective as a guide for nerve regeneration, above all for the possibility of use the polymer as a carrier for neurite-promoting factors.

[Tubulization in the reconstruction of the peripheral nervous system: the current status of experimentation]. / La tubulizzazione nella ricostruzione del sistema nervoso periferico: stato attuale della sperimentazione.

The interest in developing a prosthesis that may be effective in nerve repair as an alternative to autologous grafts, promotes experimental investigations in order to improve the so called tubulization techniques. A review of the literature of the last 10 years is performed to draw an outline of the state of the research, pointing out three main topics: the animal model, the type of the conduit and the length of the repaired gap. The rat, the rabbit and non human primates are the species with which experimental models are most often fashioned for this purpose. Among the great number of investigated conduits, interesting perspectives are arrived at mainly by those obtained with biologic or degradable materials; until now, experimental nerve defects of 3 cm or less are better repaired with artificial guides while unsatisfactory results were reported for the repair of longer gaps. The introduction in the micro-environment of the conduit of neurotrophic substances represents a challenge for the future development of these investigations aimed at improving healing and obtaining nerve regeneration through extensive defects.

[Repair of nerve defects with autotransplants]. / Zameshchenie defektov nerva s pomoshch'iu autotransplantata.

Over 15 years (1985-1999) 60 plastic reconstructions of nerve defects with autograft were performed after peripheral nerves injuries of the upper limbs (42 patients), lower limbs (14) and face (4). It is demonstrated that efficacy of surgery depends on period from injury to surgery, age of patient, length of autograft, nature and location of injury, kind of injured nerve. Better results were achieved after operations on peripheral nerves of the upper limbs. After operations on lower limbs more favorable results were achieved in repair of tibial nerve defects. Plastic surgery of facial nerve defects gave satisfactory results. Time from injury to surgery is the main factor essential for surgery result.

Intraoperative mapping of roots, plexuses, and nerves.

The use of intraoperative mapping of neural structures has come to be an indispensable technique to prevent or minimize postoperative morbidity. In this article, I briefly mention its use in mapping nerve roots, plexuses, and peripheral nerves. The reader may find some mention of monitoring techniques, too, as monitoring and mapping are seldom done separately. I include the technical details of different mapping modalities, relevant anatomy, and clinical applications, as appropriate.