In vivo study of ethyl-2-cyanoacrylate applied in direct contact with nerves regenerating in a novel nerve-guide.

Stitch suture is still the most recommended method to hold a nerve-guide in place but stitch suture is a well known cause of local inflammatory response. Glues of several kinds have been proposed as an alternative but they are not easy to apply in a real surgical setting. In 2006 authors developed a new concept of nerve-guide termed "NeuroBox" which is double-halved, not-degradable and rigid, and allows the use of cyanoacrylic glues. In this study, Authors analyzed histologically the nerve-glue interface. Wistar rats were used as animal model. In group 1, animals were implanted a NeuroBox to promote the regeneration of an experimentally produced 4 mm gap in the sciatic nerve. In group 2, the gap was left without repair ("sham-operated" group). Group 3 was assembled by harvesting 10 contralateral intact nerves to document the normal anatomy. Semi-thin sections for visible light microscopy and ultra-thin sections for Transmission Electron Microscopy were analyzed. Results showed that application of ethyl-2-cyanoacrylate directly to the epineurium produced no significative insult to the underlining nerve fibers nor impaired nerve regeneration. No regeneration occurred in the "sham-operated" group.

In vivo regeneration of rat sciatic nerve in a double-halved stitch-less guide: a pilot-study.

It is about 20 years that tubular nerve guides have been introduced into clinical practice as a reliable alternative to autograft, in gaps not-longer-than 20 mm, bringing the advantage of avoiding donor site sacrifice and morbidity. There are limitations in the application of tubular guides. First, tubular structure in itself makes surgical implantation difficult; second, stitch sutures required to secure the guide may represent a site of unfavorable fibroblastic reaction; third, maximum length and diameter of the guide correlate with the occurrence of a poorer central vascularization of regenerated nerve. We report on the in vivo testing of a new concept of nerve-guide (named NeuroBox) which is double-halved, not-degradable, rigid, and does not require any stitch to be held in place, employing acrylate glue instead. Five male Wistar rats had the new guide implanted in a 4-mm sciatic nerve defect; two guides incorporated a surface constituted of microtrenches aligned longitudinally. Further five rats had the 4-mm gap left without repair. Contralateral intact nerves were used as controls. After 2 months, nerve regeneration occurred in all animals treated by the NeuroBox; fine blood vessels were well represented. There was no regeneration in the un-treated animals. Even if the limited number of animals does not allow to draw definitive conclusions, some result can be highlighted: an easy surgical technique was associated with the box-shaped guide and acrylate glue was easily applied; an adequate intraneural vascularization was found concurrently with the regeneration of the nerve and no adverse fibroblastic proliferation was present.

A Flexor Digitorum Superficialis Tenodesis Technique for Surgical Treatment of Finger PIP Joint Volar Plate Chronic Avulsion.

Background: Chronic, post-traumatic, avulsion of the proximal interphalangeal (PIP) joint volar plate represents a disabling lesion. The purpose of this report is to describe a flexor digitorum superficialis (FDS) tenodesis using a mini-bone anchor inserted into the proximal phalanx, and its clinical outcome. Methods: 15 patients with chronic post-traumatic hyperextension instability of the PIP joint were treated surgically. From the first post-operative day patients were invited to start an early gradual joint active motion, wearing an extension block splint. Forty days after surgery, clinical evaluations were carried out, including: joint stability, pain and range of motion (ROM). The use of a circumferential splint was recommended for two further months, avoiding strenuous manual activities. The range of motion, time lost at work and the functional results were recorded six months after surgery. Results: At last follow up, 7 of the 13 reviewed patients presented an excellent functional recovery, with complete resolution of pain and stability with attainment of ROM comparable to the contralateral finger. The others 6 patients obtained good results, with remission of the functional impairment and pain, with either residual hyperextension or flexion contracture. There was one case of recurrence consecutively to a premature traumatic work-related activity. Conclusions: The FDS tenodesis via a bone anchor, combined with early active PIP joint protected motion, was shown in this study to be effective and reliable.

Spontaneous gait recovery after sciatic nerve transection impairs the non-invasive evaluation of artificial nerve guides in rats.

PURPOSE: The study of the in-vivo regeneration of a nerve, made by purely histological methods, requires a high number of animals: this poses serious problems of technique, ethics and funding. A cheaper analysis, performed on the same animal along the duration of a study, is seeked with favour and Authors wanted to evaluate gait recovery after sciatic nerve transection as a non-invasive method to evaluate the performance of an artificial nerve-guide in rats. METHODS: Male Wistar rats (n=16) were divided into three groups: in group A (n=5) the experimental gap produced was bridged by a custom-made guide; in group B (n=7) animals were "sham-operated"; in group C (n=4) a PMMA cap sealed the proximal nerve stump. RESULTS: In group A a regenerated nerve was retrieved after 8 weeks, in all animals. In group B it was possible to retrieve mostly bulbous neuromatous stumps. In group C all the animals presented a voluminous neuroma. Signs of auto-mutilation had the following distribution: 1/5 in group A; 4/7 in group B; 3/4 in group C. A clear difference in gait recovery exists only between group C (no recovery) and the two other groups (early recovery in both). CONCLUSIONS: The present study highlights that in the male Wistar rat sciatic model a spontaneous recovery in gait pattern occurs very early (within the first or second week); with this animal model, a recovery in gait is likely to ensue irrespective of the kind of device eventually tested since it may happen even without a device.

Plantar pressure distribution in patients with neuropathic diabetic foot.

PURPOSE: To describe the plantar pressure distribution in a selected group of patients with diabetic foot and to highlight their alterations in gait cycle, which follow the involvement of the foot in systemic diabetic neuropathy. METHODS: Ten patients with diabetic foot due to insulin dependent diabetes mellitus (IDDM) were studied. Gait cycle kinematics were video-recorded, both in frontal (AP view) and in sagittal (LL view) planes. Plantar pressure measurements+ APview+LLview were synchronized and compared to a computer-graphic generated skeletal model of the foot. RESULTS: In diabetic neuropathic patients, there was a prolonged interval between heel strike and toe-off with respect to normal controls. A limited motion, quite close to frank rigidity, affecting the mid-tarsal, sub-talar and ankle joints was noted. There was an early transfer of load from rear to front-foot. Shear stresses appeared. Metatarsal heads were overloaded both in mag-nitude and in time. Areas of overload present in the static plantar pressure measurement correlated poorly with areas of over-load in dynamic plantar pressure measurement and areas where ulceration was present. CONCLUSION: Prolonged duration of the gait cycle and shear stresses characterize the plantar pressure pattern of diabetic neuropathic patients. Furthermore, results suggest that static plantar pressure measurement has no clinical correlation with areas where ulcerations are present. (Journal of Applied Biomaterials and Biomechanics 2005; 3: 61-4).

Autosomal dominant transmission of bilateral "opposable" triphalangeal thumb.

Triphalangeal thumb occurs in two functional types: opposable and non-opposable. The opposable type presents a rudimentary middle phalanx and the thumb is frequently angulated. The non-opposable type presents a finger-like thumb (five-fingered hand). Triphalangeal thumb often occurs in syndromes where other anomalies are present, so its pattern of inheritance has often been described jointly with the syndrome itself, then conflicting patterns of inheritance have been reported in literature. The present study reports upon the character of "bilateral opposable triphalangeal thumb" occurring isolated, without association of other anomalies. Authors studied the phenotype distribution in a family over five generations. They found that this character is transmitted with an autosomal dominant pattern of inheritance, and affected individuals are heterozygotes.

Treatment of the sequelae of primary pathology of the hip by correction osteotomy and femoral lengthening using a combined external fixator.

It is not an exceptional event to observe the sequelae of primary pathology of the hip in young patients that, as such, are not of the ideal age for replacement surgery. Moreover, one must not overlook the difficulties involved in replacement surgery for the treatment of inveterate modifications in the normal hip anatomy. Often, among the sequelae of primary pathology of the hip, deformities of the lower limb must also be included, associated or consequent, which also need treatment. For these reasons, the authors, in three selected cases, used a combined external fixator (circular and lateral) by means of which they were at the same time able to correct the axial deformity (with a support osteotomy), and the residual hypometria (with femoral lengthening). Osteotomy plus lengthening, using an external fixator, avoid hypometria of the limb and deformity in valgus of the knee, and allow for results which would otherwise not be obtained with replacement surgery alone.

The effectiveness of the circular external fixator in the treatment of post-traumatic of the tibia nonunion.

Authors report the results they obtained when the Ilizarov circular external fixator was used for the treatment of post-traumatic nonunion of the tibia. A total of 20 patients were treated. Of these 12 had been submitted to treatment elsewhere and using other methods; 9 presented with septic nonunion; 10 revealed radiographic findings of atrophic nonunion, and 10 were hypertrophic. There was axial deviation in 18 patients. The results of treatment were always: healing of the nonunion; functional recovery of the limb; correction of leg length discrepancy; recovery of the mechanical axis. The mean stabilization time (days between the application and the removal of the fixator) was 138 days. The Ilizarov method thus proved that it was effective in the treatment of post-traumatic nonunion of the tibia where other types of treatment had failed.

A modified spica-splint in postoperative early-motion management of skier's thumb lesion: a randomized clinical trial.

BACKGROUND: Rupture of ulnar collateral ligament of the thumb (UCL) represents a frequent injury of the hand. Surgical repair is considered the gold standard but postoperative immobilization causes partial stiffness in a percentage of cases. AIM: The aim of this paper was to assess the effectiveness of a postoperative functional hand-based splint for the thumb which allows immediate postoperative motion. DESIGN: Randomized prospective clinical trial. SETTING: The study was carried out at the Orthopedics and Hand Surgery Unit of The Catholic University School of Medicine, Rome, Italy. POPULATION: Thirty consecutive patients, with a diagnosis of acute complete tear of the UCL, were selected to be treated surgically (predominantly men, mean age 39). Cases presenting associated injuries were not included. METHODS: Patients were randomized postoperatively into 2 groups of 15 (one using the new splint and the other using a standard spica splint). After four weeks of splinting, clinical outpatient evaluations were carried on (at one, two, six, twelve months) on both groups to evaluate: joint stability; pain; pinch strength; range of motion; time lost from work; sessions of physiotherapy. RESULTS: Immediate postoperative motion of the operated joint produced faster and better functional results. No cases of recurrence were recorded. CONCLUSIONS: Surgical repair, combined with active metacarpophalangeal motion allowed by the new functional splint, was effective, safe and well tolerated. CLINICAL REHABILITATION IMPACT: Enhancing the patients' function and reducing the time of functional recovery, the reported treatment presents potential advantages in the management of this frequent acute hand injury.

Abductor pollicis longus hemitendon looping around the first intermetacarpal ligament as interposition following trapeziectomy: a one-year follow-up study.

BACKGROUND: Trapeziectomy and ligament reconstructions are favoured by surgeons concerned that telescoping of the thumb may reduce its function. However, theoretically ligamentoplasties are at risk to develop tendinosis or tendon rupture or trigger a complex regional pain syndrome type 1. HYPOTHESIS: Authors tested the looping of a slip from the abductor pollicis longus (APL) tendon around the first intermetacarpal ligament. They intended to use a surgical treatment which does not require bone tunnelling or looping around a tendon. Their results support the hypothesis that this new technique is a valid addition among treatments for carpometacarpal arthritis. PATIENTS AND METHODS: Forty-two patients were followed up to one year. Each patient had subjective assessment for: pain; function (DASH score); overall satisfaction. An objective assessment was used for: first web span angle; abduction and opposition; key pinch; grip strength. Tests were performed prior to surgery, then at three, six and 12 months. X-ray films were taken to monitor thumb height. RESULTS: A substantial improvement in all these parameters was measured in all patients. X-ray films showed the mantainance of a physiological heigth after one year. We recorded one complication of keloid and two of temporary dysesthesia but no case of tendinosis, delayed rupture, or CRPS 1. Mean operative time was 27 minutes. DISCUSSION: Simplification and search for a technique which avoids the looping around a tendon is why the authors undertook this study. Advantages are the small number of required steps, short time of surgery and comfortable postoperative rehab regimen for the patient. The technique provides a distal anchoring point (without bone tunnelling). It is quite respectful of anatomy and physiology, in minimizing the re-routing of functioning tendons. We propose it as an effective procedure both to expand the armamentarium for treating the thumb carpometacarpal joint osteoarthritis and/or to simplify the ligamentoplasties already in use.

Distal radius fractures: treatment using the Epibloc system.

The Epibloc system of percutaneous endomedullary internal fixation is best indicated for AO type A2-3 extra-articular fractures of the distal radius and AO type C1 slightly comminuted articular fractures. This system includes pins that can be inserted into the medullary canal and advanced without breaking through the second cortex. This fixation is stabilised by an external plate and rendered dynamic by the pins' elasticity which compresses the fractured surfaces. Moreover, this system results in transversal ligamentotaxis which helps prevent secondary reduction losses. The result of a preliminary series of 326 cases is evaluated.

In vivo assessment of the osteointegrative potential of phosphatidylserine-based coatings.

The successful implantation of titanium-based implants for orthopaedic and dental applications is often hindered because of their mobility, which arises because of a lack of direct binding of the metal surface to the mineral phase of the surrounding bone. Ceramic coatings, although ensuring the integration of the implant within the tissue, are unstable and carry risks of delamination and of failure. Recently, a novel biomimetic approach has been developed where porous titanium implants are coated with calcium-binding phospholipids able to catalyse the nucleation of discrete apatite crystals after only 30 min incubation in simulated body fluids. The present work assesses the osteointegrative potential of this new class of coatings in an in vivo rabbit model and compares its performance with those of bare porous titanium and hydroxyapatite-coated titanium. The data obtained show that phosphatidylserine-based coatings, whilst resorbing, drive the growing bone into apposition with the metal surface. This is in contrast to the case of bare titanium.

Energy dispersive analysis (EDX) of a degradable bioactive-glass coating on Ti6Al4V in-vivo.

The bioactive-glass coating of metallic substrates provides a gradually degrading interface which can be used to favor the bony integration of the implant by the physiologic processes of bone turn-over and remodeling. Twelve New Zealand White rabbits, about 2700 g of weight, were operated by the sagittal insertion of a bioactive-glass coated plate of Ti6Al4V. Retrievals were performed at 4, 8 and 12 weeks. Undecalcified specimens were embedded in methyl-metacrylate and sectioned at 100 microns of thickness. Blocks were grinded and had an electroconductive coating to be examined by scanning electron microscopy (SEM), back scattering electron microscopy (BSEM) and X-ray energy dispersive spectroscopy microanalysis (EDX). EDX allows to evaluate quantitatively the gradual process of coating degradation. Areas of 200 microns in square were analyzed at the interface between bone and coating to determine their elemental composition. Silicon was the key marker for the presence of the glass. Morphological analysis confirms that a tight apposition with bone can be obtained by utilizing the bioactive glass coating of metal. Results of energy dispersive analysis support the mechanism of a gradual degradation of the bioactive glass coating and its integration with bone, since the presence of silicon can be documented within the newly formed bone after the coating has disappeared.

Histomorphological study of bone response to hydroxyapatite coating on stainless steel.

Bone response to hydroxyapatite coating on stainless steel has not been so extensively tested in animals as it happened for other metallic substrate, like Ti6Al4V. For this reason, authors performed an in vivo histomorphological electron microscopic study of hydroxyapatite coating on duplex stainless steel cylinders, to gather further evidences on the characters of bone apposition at the interface. Sixteen HA-coated cylinders were implanted in the distal femur of New Zealand White rabbits. Comparison with uncoated controls was made. Retrieval steps were at: 4, 8, 26 and 34 weeks. Specimens were analyzed in a Jeol JSM 6301F scanning electron microscope. The response to HA-coated samples has a morphological character of tight apposition between bone and coating. Osteocytic lacunae may be found few microns close to the coating and newly formed bone is extremely interlocked with it so that even an higher magnification electron-microscopy cannot resolve any discontinuity in between. Pictures of physiological bone-turnover are distinguishable at the bone-coating interface; areas of well preserved coating may be present together with areas where local exfoliation or fragmentation has already completely exposed the metallic substrate. On the opposite in uncoated samples, despite a morphological picture of properly formed bone, the largest area of the metal has no direct apposition with it.

Comparison in in-vivo response between a bioactive glass and a non-bioactive glass.

The authors report on the in-vivo comparison, in the rabbit, between the response to a bioactive glass and the response to a non-bioactive glass. Implants have been performed in muscle and bone. Two different glasses were investigated, namely B01 and I02. B01 is a glass designed to be degradable and resorbable and has a percentual molar composition of: SiO2 49.6%; P2O5 2.7%; CaO + MgO + Na2O + K2O + Al2O3 47.7% with a 1 : 1 CaO/Na2O ratio. I02 is a sodium-calcium-silicate non-resorbable glass lacking P2O5 and has a percentual molar composition of: SiO2 70.7%; CaO + MgO + Na2O + K2O + Al2O3 29.3%. In-vivo tests were planned as: (a) intramuscular implants of glass cylinders in the rectus femoris and retrievals took place at 2, 16 and 43 weeks; (b) intraosseus implants of glass cylinders in the distal femural canal and retrievals took place at 8 and 43 weeks. Histology and light microscopy analysis followed. Bioactive degradable glass elicits a favorable response both in muscle and bone; a gradual degradation process leads to disruption and partial resorption of the material and a tight apposition is promoted with the newly formed bone. The non-bioactive sodium-calcium-silicate glass (named I02) may elicit, like the bioactive degradable B01, a favorable response which is characterized by the absence of inflammatory or other adverse reactions; anyway it does not change its structure at an optical microscopic level and it does not promote any tight apposition with bone.

Bone response to polymers based on poly-lactic acid and having different degradation times.

Authors studied two degradable and resorbable polymers derived from lactic acid: poly-L-Lactic acid (PLLA), with a relatively long time of degradation (longer than 6 months, PL10 Purac NL); poly-DL-Lactic acid (PDLLA), with a relatively short time of degradation (shorter than 6 months, PDL Purac NL). The animal species was the young adult New Zealand White rabbit. The in-vivo study was performed by implantation of small cylinders of 10 x 3 mm in size (length x diameter) in the distal metaepiphysis of the femur; 34 cylinders have been implanted. Retrievals of PLLA specimens took place at 3, 6, 9, 12 and 24 months; for PDLLA specimens at 1, 2, 4 months. Polarized light microscopy of undecalcified tissue sections was performed. The analysis for PLLA and PDLLA has shown a favorable response of bone tissue: alterations in the bone repair, growth and remodeling have not been observed. PLLA is persistent at the times studied; there is never a tight apposition between bone and PLLA implant and an intervening fibrous layer has often been observed. PDLLA is not persistent at the times studied and it degrades quite fast; bone repair of the empty implantation's hole occurs by bony growth from the endosteal trabeculae. The newly formed bone covers the hole's walls with an elongation parallel to them. For both polymers, whether the degradation is fast or slow, the material's substitution by newly formed bone never starts from the walls of the implantation hole. Only after the complete disappearance of the polymeric material newly formed bone begins to fill the hole.

Response to polyetherimide based composite materials implanted in muscle and in bone.

The in-vivo response to a composite material obtained with polyetherimide (PEI) reinforced with carbon/glass fibers was investigated by histological methods by implanting cylinders in muscle and in bone of the New Zealand White rabbit. A common metallic alloy, widely used in orthopaedic surgery, was used as control (Stellite). The aim of the study was to analyze the biological response towards the surface of the material. Composite implants and metallic implants did not induce adverse or inflammatory reactions. The morphological picture produced was similar, in muscle and in bone, for both materials. In muscle, cylinders were confined by an extremely thin fibrous layer and the overall appearance of the muscular tissue was normal. In bone, cylinders were confined by a nearly annular rim of newly formed bone. From these data it is possible to derive that the response to PEI-based composite material is comparable with the response to metallic substrate and, then, the material can be suitable for clinical application.