Search

The psychoacoustical literature contains multiple reports about small differences in performance depending upon the sex and phase of the menstrual cycle of the subjects. In an attempt to verify these past reports, a large-scale study was implemented. After extensive training, the performance of about 75 listeners was measured on seven common psychoacoustical tasks. For most tasks, the signal was a 3.0-kHz tone. The initial data analyses failed to confirm some past outcomes. Additional analyses, incorporating the limited information available about the racial background of the listeners, did confirm some of the past reports, with the direction and magnitude of the differences often diverging for the White and Non-White listeners. Sex differences and race differences interacted for six of the seven tasks studied. These interactions suggest that racial background needs to be considered when making generalizations about human auditory performance, and when considering failures of reproducibility across studies. Menstrual differences were small, but generally larger for Whites than Non-Whites. Hormonal effects may be responsible for the sex and cycle differences that do exist, and differences in intra-cochlear melanocytes may account for the race differences.

Performance was measured on seven common psychoacoustical tasks for about 75 highly trained subjects. Because some psychoacoustical outcomes varied by race, the subjects were partitioned into White and Non-White categories for analysis. Sex, race, and menstrual-cycle differences in performance are described in a companion paper [McFadden, Pasanen, Maloney, Leshikar, and Pho (2018). J. Acoust. Soc. Am. 143, 2338-2354]. Also measured for all subjects were three types of otoacoustic emissions (OAEs): spontaneous otoacoustic emissions (SOAEs), click-evoked otoacoustic emissions (CEOAEs), and distortion-product otoacoustic emissions (DPOAEs). The experimental question was whether and how OAEs were correlated with psychoacoustical performance. In accord with past findings, the SOAEs and CEOAEs exhibited substantial sex and race differences, but the DPOAEs did not. Somewhat surprisingly, the correlations between OAEs and psychoacoustical performance were generally weak. No form of OAE was highly correlated with any psychoacoustical task for both sexes within a race category. Thus, there was no compelling evidence that the mechanisms underlying OAEs also contribute systematically to performance in any of the simultaneous or temporal masking tasks studied here. Especially surprising were the weak correlations between OAEs and detection of a tone in the quiet. Apparently individual differences in psychoacoustical performance reside more in post-cochlear (neural) mechanisms than in individual differences in the cochlear ("mechanical") mechanisms underlying the OAEs measured here.

According to the U.S. Department of Labor, the number of people who volunteered rose from 59.8 million in 2002 to 65.4 million in 2005. Those volunteering benefit from their activity in various ways; however, these benefits are non-pecuniary and are generally not recognized in the national economic accounts used to measure gross domestic product (GDP). This paper uses data from the 2002–05 Current Population Survey Volunteer Supplements to assign a dollar value to volunteering. Different methodologies yield annual estimates from $116 to $153 billion (in 2005 dollars) over the four years (between 0.9 and 1.3 percent of 2005 GDP). Additionally, characteristics of individuals most likely to volunteer are identified. The volunteer rate varies by demographic characteristics in addition to geographic location, labor force participation, and business sector. Furthermore, the data suggest that volunteering is a “normal good” because participation increases with income even after controlling for observables.

We have studied the effects of sustained local anaesthesia on postoperative mobilization of the injured hand. Small epidural catheters were placed adjacent to the peripheral nerves providing sensation to the involved part of the hand under direct vision in the distal forearm. Repeated doses of 0.5% bupivacaine were then administered during mobilization therapy to relieve pain. Fourteen out of 24 digits (60%) recorded 30° or more increases in active range of motion after bupivacaine injection. The cases that failed to improve had suffered severe injuries. Complications were few and were easily managed as the catheters were distal, superficial and accessible. This is an effective, specific and safe method of providing sustained postoperative analgesia for mobilization.

Performance was measured on several common psychoacoustical tasks for about 70 subjects. The measures included simultaneous and temporal masking, masking by tones and by complex sounds, critical bandwidth, release from masking, and detection in the quiet. Also measured were spontaneous, click-evoked, and distortion-product otoacoustic emissions (OAEs) and auditory evoked potentials (AEPs, short and middle latency). Of interest were the correlations between psychoacoustical performance and the various physiological measures as well as any mean differences by sex and by menstrual cycle. Subjects were tested behaviorally in same-sex crews of 4–8 members, and behavioral testing required from 8 to 10 weeks for each crew. Correlation and effect size were the primary measures of interest. Resampling was used to determine implied significance for the various comparisons studied. Some correlations between physiological measures were moderately high, but the correlations between psychoacoustical tasks and the diffe...

Performance was measured on several common psychoacoustical tasks for about 70 subjects. Subjects were tested in same-sex crews of 4—8 members. Testing required 8—10 weeks for each crew to assure that all subjects were well practiced on all tasks. Of initial interest were any differences by sex and by menstrual cycle. Correlation and effect size were the primary measures of interest. Resampling was used to determine implied significance for the various comparisons studied. During analysis, racial background turned out to be a relevant variable; because this was unexpected, recruitment by, and documentation of, race was poor, so the best we could do was categorize subjects as Non-White or White. For essentially all of the psychoacoustical tasks measured, the sex and menstrual differences were non-significant when the results were pooled across race. However, when the subjects were partitioned by race, small-to-moderate sex and menstrual differences did emerge, primarily for the White subjects. Correlations...

Limb salvage in children with primary malignant bone tumours around the knee is challenging, with considerations such as shortening, bone and joint remodeling and high functional demands of active children. The ultimate aim for reconstruction is restoring a stable, painless and mobile joint. With improved survival rates from chemotherapy, reconstructive techniques should ideally last the child's lifespan. We adopted a biological approach by preserving the patients' native joint, with bony defects bridged by fibula grafts supplemented by autoclaved bone grafts infused with bone marrow. We conducted this retrospective review to determine if we were able to meet our objectives of reconstruction.A retrospective review of children with osteogenic sarcoma involving the distal femur or proximal tibia treated at our institution was done. Patients aged 13 years and below at the time of surgery who had undergone a limb salvage procedure that preserved the knee joint were included.Nine patients were identified, 3 males and 6 females. The average age was 10.0 years (range, 7 to 13 years) at the time of surgery. Seven had tumours involving the distal femur while 2 had tumours involving the proximal tibia. There were no cases of local recurrence. Four of the 9 patients died from metastatic disease, the 5 surviving patients have no evidence of disease, and the average follow-up for survivors was 13.2 years. The average active range of motion for the knee joint was 96° (range, 50° to 130°). The average Musculoskeletal Tumour Society (MSTS) score was 26.3 (range, 23 to 30).We have observed this technique of limb salvage offers satisfactory limb function with long-term follow-up.

The value and impact of esthetic prostheses on amputee rehabilitation and their long-term use were evaluated in 89 patients. The outcomes were found to have no correlation with the severity of injury and level of amputation. The utilization rate for digital prostheses fitted for single-digit amputations after 5 years was 63%, whereas that for multiple-digit, hand, and more proximal amputations remained consistently high at more than 80%. The high prosthesis utilization in the authors' series could be attributed to the availability of an adjunct prosthetic program.

A free vascularized fibular bone transfer was successfully performed in a 1-year-old child to reconstruct the loss of the right humeral shaft following neonatal osteomyelitis. Subsequent growth of the child resulted in gross arm length discrepancy, with associated functional deficits. Callostatic distraction-lengthening of the vascularized fibular graft was carried out to compensate for this limb length discrepancy by using an Ilizarov external fixator. Lengthening of 6 cm over a 3-month period, representing a 75% increase in the original length of the transplanted fibula, was achieved. Active bone regeneration, good corticalization and endosteal medullary cavity formation was observed in the lengthened fibula. The combined modalities of vascularized bone transfer and Ilizarov callostatic distraction-lengthening offer a solution for reconstruction for large segmental bone loss associated with growth arrest of the epiphyseal plates in children.

A detailed anatomic and intramuscular neural staining study in 22 human and 5 monkey upper limbs revealed that the flexor carpi radialis can be raised on its proximal neurovascular pedicle and that the muscle can be split along its tendon into two independently functioning neuromuscular compartments, each with its own nerve and blood supply. A study of the muscle architecture in the human specimens found the radial compartment to have significantly longer fiber length and a larger physiologic cross-sectional area than the ulnar compartment. Independence of function of each compartment was demonstrated in electrical stimulation studies in six monkeys (Macaca fascicularis), but no significant difference was noted in the peak isometric load between the two compartments (p = 0.68) in the monkey. The extra functioning muscle units become important in local transfers for restoring function in multiple nerve palsies as in Hansen's disease, severe traumatic loss of muscle in crush injuries and compartment syndromes, and after wide resection in infective and neoplastic conditions in the forearm and hand.

A combined one stage anterior and posterior approach was used to excise a giant cell tumor involving the second lumbar vertebra. The tumor involved the anterior and posterior elements of the vertebra. A wide excision was feasible with immediate stabilization using the Luque instrumentation posteriorly and fibular strut grafts supporting the vertebral bodies anteriorly. The followup period was 13 years. There is no recurrence, and the patient has no symptoms of disease, and the fibular grafts are fully incorporated.

A comparison of the gross anatomic extramuscular nerve branches, and intramuscular blood supply of the gracilis muscle showed similar patterns in both monkey and human. The number and pattern of distribution of the extramuscular terminal branches to the muscle were similar. The intramuscular neural pattern demonstrated with the Sihler's staining technique was also similar in both species. In vivo electrical stimulation studies in the monkeys revealed that stimulating each extramuscular terminal nerve branch produced a distinct segmental contraction of the muscle. Independent contraction with force generation was observed when the monkeys muscle was split into anterior and posterior segments and stimulated through each of the two subdivisions of the main nerve trunk to the muscle. Angiograms verified that circulation was preserved in these two segments.

Microsurgical reconstruction of the severely mutilated, hand aimed at improving prehensile functions often does not address the esthetic aspects of the hand. The poor appearance of the reconstructed hand affects its active display and use. A, hand-glove prosthesis may be prescribed in this instance to enhance the overall form and function of the mutilated, hand. We reviewed 16 cases of mutilating hand injuries in which surgical reconstructions were performed and the patients were subsequently fitted with a hand-glove prosthesis to augment the outcome. An improved appearance, was achieved in all patients fitted with the prosthesis. The patients' sense of confidence was also enhanced, which in turn promoted the active and open use of the reconstructed hands. While prescribed primarily to improve the appearance of the reconstructed hands, these prostheses were documented to enhance the physical hand functions, in 11 cases by increasing the span of the hand and providing and opposable post and a palmar base for holding and for anchorage. The prosthesis enhanced assitive functions of the reconstructed hands and free the contralateral normal hand for use in bimanual activities, such as holding a wallet and taking out money supporting a note pad for writing, and holding a plate at buffet receptions. At the 18-month follow-up visit, 12 (87%) of the patients continued to use their prosthesis. Wear and tear were problems associated with the frequent use of the prosthesis. The expected life span of the prosthesis with daily use ranged from 2 to 3 years. All the patients acknowledged that the prosthesis played a role in their rehabilitation and that it helped them to overcome the initial psychological trauma and to come to terms with their physical loss.

Fixation of small bones in the adult and the child’s hands remains a challenge. The authors present a technique of bone fixation using customized staples made intraoperatively from K-wires (0.9–1.6 mm in diameter). Their specific purpose was to provide axial alignment and rotational stability for carpal bone fixation and for epiphysiodesis in phalanges. This technique was used in 14 cases (11 adult and three paediatric). No bone shattering, implant breakage, implant loosening or infection occurred. As K-wires are quite malleable, custom sized and shaped staples which follow the bone contours could be made to give a more exact fixation. All cases had satisfactory outcomes, achieving the preoperative objectives of bony fixation. This method is safe, precise and technically easy. It is also relatively cheap and only requires simple, standard instruments.

The volume of the volar soft tissue, dorsal soft tissue, and bone and the area of the dorsal and volar surfaces were estimated in 35 adult cadaver fingertips. The fingertip was defined as the part of the finger distal to the plane of the palmar skin crease and the major dorsal crease at the distal interphalangeal articulation. An impression molding technique, involving silicone rubber, was used to determine the volume, while dyed imprints of the dorsal and palmar surfaces were used to determine the surface area. In all digits, the mean volume of the volar soft tissue of the fingertip was found to be about 56%, the dorsal soft tissue about 26%, and the volume of bone about 18%. The volar soft tissue includes the skin and fascia (51% of the total fingertip volume), the flexor tendon and its sheath, and the volar plate and volar joint capsule (5% of the total). Power relationships for the total fingertip volume, the volume of volar soft tissue, and the volume of bone in terms of the length of the fingertip were noted. There was also a linear relationship found between the volume of the volar soft tissue and the volar surface area. This study provides data on the ratio of soft tissue to bone in the fingertip. The maintenance of the soft tissue-to-bone ratio, so as to regain fingertip form and function, may be of particular importance when designing flaps and coverage in the reconstruction of the fingertip.

Background The information available on innervation pattern of the human forearm muscles in standard anatomy texts, although adequate for routine procedures, is not detailed enough for surgical reconstruction in complex injuries of the limb and for paralytic conditions of the forearm from peripheral nerve and spinal cord injuries. Methods: The innervation pattern in 10 cadaveric forearms was studied. The contributions of the main nerve trunks to each forearm muscle was examined. The location and number of the primary motor nerve branching points and of the terminal nerve entry points to each muscle were investigated. The location of both the primary nerve branching points and terminal nerve entry points was presented as a percentage of forearm length measured from the lateral humeral epicondyle to the radial styloid. Results: Seven of 19 forearm muscles were innervated from a single branch from the main nerve trunk. The remaining 12 received more than one primary branch. Two of 19 forearm muscles had only one terminal nerve entry point. The others had two or more each. In 13 of 19 forearm muscles, the statistical median location of the primary motor nerve branching points was within the proximal one-third of the forearm length and either more proximally or distally for the remainder. The statistical median location of the terminal nerve entry points was within the proximal one-third in 9 forearm muscles and within the middle one-third of the forearm in 8 forearm muscles. In two, it was located proximal to the elbow and in the distal one-third of the forearm, respectively. Conclusions: In lacerations across the forearm, where main nerve trunks are divided, mere repair of the nerve trunks would not address the denervation of muscle or segments of muscle by the division of the primary (or secondary) nerve branches traversing the wound and which took origin proximal to the laceration either from the divided nerve trunks or from other undamaged nerve trunks. Although the main nerve trunks may be intact, segmental crush injuries will defunction muscles by direct muscle damage or by damage to the terminal nerve entry points to the muscle. Knowledge of the location of the nerve branches and the terminal nerve entry points facilitates the insertion of electrodes at the motor points of forearm muscles for functional electrical stimulation in upper motor neuron lesions. The information in this study may also be usefully applied in selective denervation procedures to balance muscles in spastic upper limbs. Anat. Rec. 248:456-463, 1997. © 1997 Wiley-Liss, Inc.

The appearance of the skin is dependent on the optical properties of the various layers of tissue and the presence of pigments. In order to reproduce the lifelikeness of the skin in developing digital prostheses, a multiple layered moulding technique was utilised. The prosthesis was moulded in two coloured layers, an outer layer and an inner layer. Four combinations of multiple coloured layers and two single coloured layers varying in their optical properties and base colours were assessed. In two groups an additional intermediate layer of detailed colours was added between the two layers, to enhance the creaselines, nails, blood vessels, and other features. All prosthesis were moulded to a total thickness of 0.6 mm. This method of moulding was based on the anatomical characteristics of the epidermal and dermal layers of the skin and their optical characteristics. The aim was to determine which combination of multiple layers gave the best outcome and made the prosthesis look lifelike in appearance. The appearance and lifelikeness of the prostheses were qualitatively assessed by a panel of assessers divided according to their vocation. The study showed that the best combination for moulding the prosthesis in multiple layers was to have the outer layer translucent and the inner layer opaque. An intermediate layer should be incorporated to enhance the more prominent surface features and the nails. The base colour of the inner layer should be darker than the outer layer to allow the intermediate layer to have a reflective background.

Background A largely forgotten technique initially designed by Sihler for staining nerve tissue has not been fully explored for staining intramuscular nerve branches in skeletal muscles. Methods Fresh, long heads of triceps from locally bred New Zealand white rabbits were used for this study. Immediately after their removal, the muscles with their motor nerve branches from the radial nerve were fixed in 10% unneutralized formalin, followed by maceration and depigmentation in 3% aqueous potassium hydroxide, decalcification in Sihler's solution I, micro-dissection, staining in Sihler's solution II, destaining in Sihler's solution I, neutralization in 0.05% lithium carbonate, and clearance in increasing concentrations of glycerin. Results A clear three-dimensional orientation of the distribution of the intramuscular nerve branches within the muscle belly was visualized. It was found in all specimens that the long head of triceps in the rabbit was constantly innervated by three main intramuscular nerve branches and each of them supplied different amounts of muscle fibers with some variation. Conclusion The Sihler's neural staining technique can be applied to the study of the distribution of intramuscular nerve branches in limb skeletal muscles. Extension of the technique may be utilised in the identification of neuromuscular compartments in skeletal muscles. Such information may be usefully applied in free muscle transfer of segments of skeletal muscle. Anat. Rec. 247:137–144 © 1997 Wiley-Liss, Inc.

Studies in animals by de Bastiani et al. (1986) on leg lengthening by physeal (growth plate) distraction have shown that the integrity of the growth plate can be preserved intact if slow rates of distraction are employed. Clinically, however, this technique has been restricted to the period shortly before skeletal maturity, due to uncertainty about the behavior of the growth plate following distraction. We conducted 2 studies. 11 immature rabbits used in a study on the normal growth at the proximal tibial physis established that the growth rate was unchanged with transfixing K-wires in the epiphysis. The normal growth rate of the proximal physis of the tibia decreased with age and was expressed as a quadratic function, Gn (mm/day) = 0.44-0.002 age (days). At 6 weeks of age, the growth rate was 0.33 mm/day, slowly decelerating to a rate of 0.15 mm/ day by the 16th week. In the lengthening study, to determine whether the growth plate would maintain a normal rate of growth following slow distraction, a custom-made bilateral distraction device was applied to the proximal tibial epiphysis of 32 immature rabbits aged 6 weeks and weighing approximately 500 gm. The growth behavior of the growth plate following 2, 3 and 4 weeks of distraction was studied. The rate of distraction was set at 0.5 mm/ day. The mean amount of distraction achieved was 8.5 mm, 11.3 mm and 14.6 mm resulting in a mean 'net' increase in length as compared to the experimental control after the distractor was removed amounting to 3.0 mm (55% of the control growth), 3.6 mm (47%) and 4.2 mm (40%), respectively. Subsequent serial measurements, up to 13 weeks postdistraction, showed no significant change in the discrepancy between the length of the tibia and the growth rate at the proximal tibial epiphysis and between the distracted and the contralateral controls in all 3 groups. Our findings suggest that the proximal tibial growth plate in the rabbit would maintain a normal growth rate after slow physeal distraction for periods up to 4 weeks.

This paper reviews the various techniques and procedures available for reconstruction of the digits to restore form and function in the aplastic hand. The author presents his own experience and discusses future trends in the management of missing digits.

This study examines our clinical experience of fitting 136 digital prostheses in 90 patients. The careful selection of patients, especially concerning their expectations, is the single most important factor for successful prosthetic development for physically suitable candidates. Whether continued disability is due to physical loss or to its emotional impact, the socioeconomic consequences are similar, so attention to both is required. In a review of 30 patients fitted with digital prostheses after a minimum follow-up time of 2 years, it was found that 22 (73%) used their prostheses daily and another 7 (23%) used them intermittently according to the occasion. Thus, a total of 29 (97%) of those fitted with our digital prosthesis continued to use them after 2 years. Technical problems, such as loose fit and perspiration, resulted in 7 (23%) of the patients using the prostheses only occasionally. Fitting a prosthesis goes beyond aesthetics, and our study confirmed that digital prostheses, if of high quality, can alone or in conjunction with appropriate surgical reconstructions restore near normal appearance and form, substantially repair damaged body image, and simultaneously improve physical capability.

Between June 1978 and July 1991, 64 limb reconstructions were done using vascularized fibular grafts. Of these, 10 became infected. Five grafts were proven viable, whereas the other 5 were proven nonviable based on the survival of the skin in the composite osteocutaneous graft and from bone scans, angiograms, and biopsies. A distinct difference in the radiologic manifestation and clinical course of the infection was noted between the viable grafts and nonviable grafts. The viable grafts showed radiologic changes of osteomyelitis that were localized, and the graft incorporated, healed with antibiotics, and exhibited graft hypertrophy. In the nonviable grafts, the radiologic changes were extensive, evidence that resorption of the grafts had resulted. This suggests that, because of the poor prognosis associated with infection of the nonviable vascularized fibular grafts, the infected grafts should be removed early to minimize the morbidity and to shorten the protracted course associated with infection. With the infected viable grafts, efforts at salvaging the graft with multiple debridements and systemic antibiotics were rewarding.

The wide range of skin tones in the Asian population presents a challenge when colour-matching hand and finger prostheses. It requires that the prostheses be custom-made to better match the wide variations. We have developed a finger and hand prosthesis using a multi-layered moulding technique incorporating a colour-matching procedure capable of reproducing the colour tones and life-like appearance of the skin. Between 1990–1994, we have fitted these prostheses to a total of 109 patients. In evaluating the colour-match of their prostheses, 84% of the patients fitted with hand prostheses and 78% of those fitted with finger prostheses had a good to excellent match. This paper discusses some of the challenges we face in colour-matching hand and finger prostheses in the Asian population.

Large bone defects in the upper limb pose many challenges in reconstructive surgery. Conventional and innovative methods have been described, employing the use of microsurgical and non-microsurgical techniques to overcome both bony and soft tissue defects. This article reviews the success and pitfalls of different techniques of reconstruction of large bone defects in the upper limb, including microsurgical transfer of the free vascularised fibula graft as a diaphyseal bone replacement and as a hemivascularised joint transplant, and non-microsurgical options using conventional bone grafting, the induced membrane technique and the role of callotatic distraction-lengthening procedures.

The fitting of short finger stumps with silicone prosthesis is a challenge because of the suboptimal finger-prosthesis contact due to length and distal tapering of digital stumps. The purpose of this report was to describe and evaluate the Micropore(™)-polyvinyl chloride tube technique for fitting short finger stumps.For a total of 10 patients, short finger stumps were fitted using the technique. A short length of polyvinyl chloride tube, trimmed and contoured to fit, was secured on the distal stump tip with Micropore tape. The prosthesis was worn over the polyvinyl chloride tube extension. Three different fitting methods were evaluated: fitting with and without the Micropore-polyvinyl chloride tube technique, and with the use of skin adhesive on the stump.All patients achieved a very secure prosthetic fit with the Micropore-polyvinyl chloride tube technique. No incidences of prosthesis slippage were reported at the longest follow-up of 30 months. The Micropore-polyvinyl chloride tube technique is an effective method for fitting short finger stumps.

The musculocutaneous nerve and its motor branches to the biceps and brachialis were dissected and studied under the operating microscope in 24 fresh-frozen cadaveric specimens. The motor branch to the biceps exits from the musculocutaneous nerve at 119 mm distal to the coracoid process. Anatomic variations were seen in the innervation of the two heads of the biceps. A common primary motor branch that bifurcates to supply the two heads was seen in 20 specimens (type I). Two specimens were observed to have two separate primary branches originating from the main musculocutaneous nerve trunk to individually supply each head of the biceps (type II). The third variation, two specimens (type III), was observed in two specimens to be similar to type I, but with an additional distal motor branch innervating the common belly of the biceps muscle. The motor branch to the brachialis muscle exists from the musculocutaneous nerve 170 mm distal to the coracoid process. A single primary motor branch (type I) was seen in 23 specimens, and 1 specimen (type II) showed two separate primary motor branches innervating the muscle. The motor branches to the biceps and brachialis muscles may be dissected proximally from their points of exit from the main trunk of the musculocutaneous nerve for a mean distance of 44 mm and 53 mm, respectively. This information can be used by surgeons who elect to suture intercostal nerves to the motor branches of the biceps and brachialis muscles for elbow flexion in brachial plexus injuries.

10 patients with primary neoplasms of the shoulder girdle underwent limb salvage procedures involving resection of the proximal humerus and parts of the scapula and clavicle. The function of the ipsilateral limb was assessed in all patients, in 9 at least one and a half years after surgery. Function was good in 3 of the 6 patients in whom an interposition bone graft was used and a successful shoulder arthrodesis was achieved. In the remaining 3, proximal arthrodesis was unsuccessful and the result was fair in 2 and a failure in 1. All 3 patients in whom the extended Tikhoff Linberg type of reconstruction was undertaken had good function although unsatisfactory cosmetic results. The 10th patient, who had a temporary cement and wire interposition, died of distant metastases 8 months after surgery and was considered a failure.

Rotational molding in two axes has the advantage of producing hollow products. Previously, the inherent difficulty was in the production of objects with uniform thickness since the speed of the two primary axes are fixed and cannot be varied independently to take into account the changes in material properties such as its density and viscosity. With the advent of computers, it is now possible to control the thickness of the object accurately. This is made possible by creating an intelligent software which takes in the viscosity and density time variation of the polymer and using the flat plate withdrawal theory, computes the new speed for each axis. The relationship between rotational molding parameters and polymeric material properties for a solvent – silicone rubber system to produce a hand prosthesis is illustrated in this paper.

Two experiments in the rabbit model have been carried out to see if a vascular pedicle placed in a growing epiphysis would establish new capillaries. In one, the vascular pedicle of peroneus longus muscle was placed in the proximal fibula epiphysis. In the other, the proximal fibula was excised and the epiphysis placed across the saphenous artery and vein in the groin. After 3 months, histological examination of the epiphyses in both experiments showed that no new vessels had grown from the vascular pedicle. Cartilage is known to inhibit vascularisation, and these results suggest that attempts to revascularise the epiphysis, for example, following Perthes' disease, may fail. For the same reason, attempting to supplement the epiphyseal vessels by implanting a new vessel before or after epiphyseal transfer may fail.

Glomus tumour is a benign lesion arising from the glomus apparatus of the skin and subcutaneous tissue. Glomangioma is the angiomatous variant, which is uncommon. We report a very rare presentation of a glomangioma with multiple recurrences. We advocate preoperative angiography to delineate the extent of the lesion to facilitate complete excision.

A method for creating a model for fabricating a partial hand glove prosthesis is described. The realigned casts of the corresponding digits of the contralateral uninjured hand were used to substitute for the lost digits on a cast of the stump. The technique allows an exact reproduction of the anatomical and fine surface details of the digits. It has the advantage of customisation, allowing a close match in the size, shape and surface characteristics of the prosthesis to that of the remaining digits of the hand.

To understand the molecular etiology of osteosarcoma, we isolated and characterized a human osteosarcoma cell line (OS1). OS1 cells have high osteogenic potential in differentiation induction media. Molecular analysis reveals OS1 cells expressing the pocket protein pRB and the runt-related transcription factor Runx2. Strikingly, Runx2 is expressed at higher levels in OS1 cells than in human fetal osteoblasts (HFOB). Both pRB and Runx2 have growth suppressive potential in osteoblasts and are key factors controlling competency for osteoblast differentiation. The high levels of Runx2 clearly suggest osteosarcomas may form from committed osteoblasts that have bypassed growth restrictions normally imposed by Runx2. Interestingly, OS1 cells do not exhibit p53 expression and thus lack a functional p53/p21 DNA damage response pathway as has been observed for other osteosarcoma cell types. Absence of this pathway predicts genomic instability and/or vulnerability to secondary mutations that may counteract the anti-proliferative activity of Runx2 that is normally observed in osteoblasts. We conclude OS1 cells provide a valuable cell culture model to examine molecular events that are responsible for the pathologic conversion of phenotypically normal osteoblast precursors into osteosarcoma cells.

Background There has been no reliable technique with which to display the innervation within whole-tissue specimens of the face. Such a technique preserves the architecture of the facial muscles and provides new data on intramuscular and sensory neural networks. Sihler's technique preferentially stains myelinated nerves within whole tissue, which is rendered transparent. On transillumination, entire neural networks can be studied in situ without the need for dissection and histologic examination. The purpose of this study was to apply Sihler's technique to study innervation patterns of the face, define end points, and improve specimen transillumination. Methods Eight macaque fascicularis monkeys were studied. The mimetic muscles of the face with intact facial nerve and sensory nerves were harvested as whole tissue composites. Sihler's technique was modified with formalin fixation before dissection to minimize autolysis of the myelin sheath. Prolonged immersion in glycerin improved tissue transparency. A replica of the skull was made with silicone and a light source embedded to restore three-dimensional configuration and provide transillumination. Results The facial nerve and sensory nerves were clearly seen up to their terminations in the transparent muscle and soft tissue. Observations were made with regard to the extramuscular and intramuscular innervation patterns of the facial nerve and sensory nerve patterns. Conclusions Sihler's technique is a simple and reliable method with which to study the innervation of the face. This process may be applied to the human face to provide a much-needed roadmap to surgery, and the primate model may be developed for the study of facial reinnervation, facial reanimation, and dynamic facial transplantation.

Purpose Soft tissue defects on the lateral borders of the digits are difficult to reconstruct using local or local–regional flaps. We describe a “palmar pivot flap” to resurface an adjacent defect on the palmar–lateral aspect of the digit. Methods The surgical technique is described. This flap is an axial pattern flap based on the subcutaneous transverse branches of the digital artery. The flap is pivoted up to 90° on the neurovascular bundle in its base, into an adjacent defect. The flap can be raised from either the proximal or the middle phalangeal segments. It can cover defects sited from the level of the proximal interphalangeal joint up to the fingertip. The donor defect is limited to the same digit and is covered with a full-thickness skin graft. Results We have used this flap on 3 patients with defects at the middle phalangeal segment, the distal interphalangeal joint, and the fingertip. All healed primarily. One patient had a mild flexion contracture of the proximal interphalangeal joint, whereas the other 2 had no complications. The patients with distal interphalangeal joint and fingertip defects had excellent sensation in the flap (2-point discrimination of 5–6 mm). Conclusions The palmar pivot flap is useful for resurfacing otherwise difficult defects on the lateral borders of the digits around and distal to the proximal interphalangeal joint, including those at the fingertip. It provides sensate, glabrous skin. The donor defect is on the same digit and is well hidden, producing an aesthetic and functional reconstruction.

This study addresses the dilemma of initial clinical and social acceptance of a newly fabricated silicone prosthesis in relation to its colour match to the natural skin. This was achieved by derivation of specific colour difference thresholds defining perceptible and acceptable levels of colour sensitivity. Two separate sets of 10 fair and dark shade digit prosthesis samples were each fabricated with a stepped increase in colour difference (deltaE) against the baseline hand prosthesis. Ninety individuals with normal colour vision scores were selected as colour assessors. The colour difference of each prosthesis in the two series was evaluated visually against the baseline by the assessors, using defined scores. The thresholds for perceptible and acceptable colour difference determined in this study were deltaE= 0.8 and deltaE= 1.8 for the fair series and deltaE = 1.3 and deltaE = 2.6 for the dark series, respectively. The acceptable threshold values differed from the perceptible threshold values by deltaE= 1.0 for the fair-shade samples and deltaE= 1.3 for the dark-shade samples. This study demonstrated that subjective visual assessment is positively correlated with deltaE values computed from colorimetric measurements for both fair and dark-shade silicone samples (p0.001). This results shows that human subjects with normal colour vision are capable of accurately assessing colour differences. These observations emphasize the importance of subjective feedback on colour by the patient, provided the latter has perfect colour-tested vision. The study also showed that human subjects were less sensitive to perceived colour differences in darker-shade than fairer-shade samples (p0.001). This finding seems relevant in a clinical setting involving a multi-ethnic patient population.

A technique for the secure fixation of acrylic nails in multilayered silicone finger prostheses is described. The secure fixation of the nail to the prosthesis is achieved by a method of "sandwiching" portions of the nail between the silicone layers of the prosthesis akin to the overlapping of the nail by the anatomical nail fold and nail wall. In addition the use of a cynoacrylate adhesive ensures strong surface to surface bonding.

A rare case of an epitheloid haemangioendothelioma presenting as an aggressive soft tissue mass in the wrist of an infant is presented. The management of the lesion presents particular difficulties because of its diffuse involvement of surrounding muscles, tendons and neurovascular bundle and the importance of preserving hand function. The epitheloid haemangioendothelioma rarely occurs extravascularly with less than 15 such cases reported in the literature.

A wide resection of a giant cell tumour involving the entire middle metacarpal is presented. Reconstruction preserving the central column and metacarpophalangeal joint was achieved using autologous iliac crest bone as a spacer and structural support. The fibro-osseous cartilage portion of the iliac graft was used as a “hemi-joint” replacement. By using a bridging bone graft and screw to fuse the adjacent proximal phalanges of the middle and index fingers, a stable “internal syndactyly” was achieved. Although independent index and middle finger motion was sacrificed, the approach allowed wide resection for local tumour control, re-established structural integrity, preserved metacarpophalangeal joint motion and allowed early motion. The aesthetic result was also good.

Trigger finger is commonly secondary to stenosing tenosynovitis. Space occupying lesions in the tendon bed, although uncommon, may prevent smooth tendon gliding. These include lipoma, anomalous muscle insertions, tumours of the tendon sheath and haemangiomas. We describe a patient who had triggering of the left middle finger at the proximal interphalangeal joint due to an exostosis blocking the flexor tendons gliding. Removal of the exostosis relieved the problem. The clinician must be aware that there are other causes for triggering. These may be identified with pertinent findings in the history and physical examination.

The foot offers numerous useful options for hand reconstruction. Hallux transfer, dorsalis pedis flap, second toe transfers, and toe joint transfers offer good functional results in reconstructed hands. However, when the donor site is repaired with skin grafts, delayed wound healing, scarring, and contractures often result. Poor cosmesis of the donor site and altered gait are the main drawbacks of the procedures. The authors propose a new concept of primary reconstruction of the donor foot using a reverse-flow anterior tibial flap from the same leg. Two flaps are raised from the same anterior tibial vessel system in continuity as a distal free flap for hand reconstruction and as a proximal reverse-flow pedicled flap to resurface the donor defect. This technique allows good flap reconstruction of the foot donor site, reducing morbidity and limiting the operation to the same limb. The authors report their experience of 33 cases. There were no failures. Primary wound healing was achieved in the foot donor site, with acceptable cosmesis and satisfactory function.