Arm transplantation: prospects and visions.

Based on the results of above-elbow replantation, it is possible that above-elbow arm transplantation will be successful and result in a superior functional outcome as defined by the Chen criteria. Above-elbow arm transplantation is probably technically simpler than distal forearm or wrist transplantation, especially since the macroanastomoses do not require microsurgical expertise. However, hand function depends on reinnervation of forearm muscles and the distance for nerves to regenerate for reinnervation of intrinsic muscles of the hand is significant. The vascularized bone marrow transplanted with the arm holds potential to induce chimerism and promote tolerance but could also make the recipient more susceptible to graft-versus-host disease. Prospective trials comparing the functional results after above-elbow arm transplantation with the functional results achieved by the best neuronal-controlled above-elbow prosthesis are warranted and will determine the gold standard of upper-extremity reconstruction.

Bone morphogenetic protein as an adjuvant in the treatment of Kienbock's disease by vascular pedicle implantation.

This case report documents the first use of bone morphogenetic protein (BMP) as an adjuvant to revascularisation with a first dorsal metacarpal arterio-venous pedicle in the treatment of a patient with Stage III Kienbock's disease. The patient had complete relief of her symptoms of wrist pain by 8 months postoperatively, when X-rays showed no further evidence of lunate collapse and an MRI scan demonstrated islands of revascularisation. It is impossible to prove unequivocably that BMP contributed to the result seen in this one patient, but this adjuvant concept is based on experimental evidence demonstrating that optimal bioengineering of vascularised bone is dependent on four factors - a structural matrix, progenitor cells, BMP and a vascular supply, and BMP may play a future role in promoting new bone formation in Kienbock's disease.

Effects of local continuous release of brain derived neurotrophic factor (BDNF) on peripheral nerve regeneration in a rat model.

The purpose of this study was to evaluate the effect of continuously released BDNF on peripheral nerve regeneration in a rat model. Initial in vitro evaluation of calcium alginate prolonged-release-capsules (PRC) proved a consistent release of BDNF for a minimum of 8 weeks. In vivo, a worst case scenario was created by surgical removal of a 20-mm section of the sciatic nerve of the rat. Twenty-four autologous fascia tubes were filled with calcium alginate spheres and sutured to the epineurium of both nerve ends. The animals were divided into 3 groups. In group 1, the fascial tube contained plain calcium alginate spheres. In groups 2 and 3, the fascial tube contained calcium alginate spheres with BDNF alone or BDNF stabilized with bovine serum albumin, respectively. The autocannibalization of the operated extremity was clinically assessed and documented in 12 additional rats. The regeneration was evaluated histologically at 4 weeks and 10 weeks in a blinded manner. The length of nerve fibers and the numbers of axons formed in the tube was measured. Over a 10-week period, axons have grown significantly faster in groups 2 and 3 with continuously released BDNF compared to the control. The rats treated with BDNF (groups 2 and 3) demonstrated significantly less autocannibalization than the control group (group 1). These results suggest that BDNF may not only stimulate faster peripheral nerve regeneration provided there is an ideal, biodegradable continuous delivery system but that it significantly reduces the neuropathic pain in the rat model.

Treatment of multiple hereditary osteochondromas of the forearm in children: a study of surgical procedures.

We have evaluated the clinical outcomes of simple excision, ulnar lengthening and the Sauvé-Kapandji procedure in the treatment of deformities of the forearm in patients with multiple hereditary osteochondromas. The medical records of 29 patients (33 forearms) were reviewed; 22 patients (22 forearms) underwent simple excision (four with ulnar lengthening) and seven the Sauvé-Kapandji procedure. Simple excision increased the mean supination of the forearm from 63.2 degrees to 75.0 degrees (p = 0.049). Ulnar lengthening did not significantly affect the clinical outcome. The Sauvé-Kapandji technique improved the mean pronation from 33.6 degrees to 55.0 degrees (p = 0.047) and supination from 70.0 degrees to 81.4 degrees (p = 0.045). Simple excision may improve the range of movement of the forearm but will not halt the progression of disease, particularly in younger patients. No discernable clinical or radiological improvement was noted with ulnar lengthening. The Sauvé-Kapandji procedure combined with simple excision of osteochondromas can improve stability of the wrist, movement of the forearm and the radiological appearance.

The development of a data model for research on the environmental correlates of physical inactivity and obesity.

Development of information systems to support research on environmental correlates of physical activity and nutrition has to date been largely ad hoc and driven by single research project requirements. In this rapidly growing field, research databases are becoming increasingly complex as researchers attempt to model the impact of multiple aspects of the environment such as neighborhood characteristics, site and building design, and nutritional environments on both aggregate and individual level measures of physical activity and weight. The presentation reports on the initial implementation of a logical data model in the context of an ongoing research program that is exploring the relation of neighborhood physical and demographic characteristics on physical activity levels measured in time and space.

Healing of a critical-sized defect in the rat femur with use of a vascularized periosteal flap, a biodegradable matrix, and bone morphogenetic protein.

BACKGROUND: The purpose of this study was to evaluate the osseous healing of a critical-sized femoral defect in a rat model with use of recombinant human bone morphogenetic protein-2 (rhBMP-2), a matrix fabricated of D,D-L,L-polylactic and hyaluronan acid (OPLA-HY), and a vascularized periosteal flap. METHODS: The carrier matrix OPLA-HY with or without rhBMP-2 was implanted in a 1-cm-long femoral defect and secured with a plate and screws. In some groups, a vascularized periosteal flap was harvested from the medial surface of the tibia. In group 1, the femoral defects in the animals were filled with the OPLA-HY matrix alone; in group 2, the OPLA-HY matrix was covered by the vascularized periosteal flap; in group 3, 20 mug of rhBMP-2 was added to the OPLA-HY matrix; and in group 4, the femoral defect containing the OPLA-HY matrix and 20 mug of rhBMP-2 was wrapped circumferentially by the vascularized periosteal flap. The presence and density of new bone formation in the femoral defect were evaluated radiographically, histologically, and with histomorphometry at four and eight weeks postoperatively. RESULTS: Groups 1 and 2, which were not treated with rhBMP-2, showed no radiographic or histologic evidence of mature bone formation at four or eight weeks. Both groups 3 and 4, which were treated with rhBMP-2, demonstrated excellent bone formation. However, with the periosteal flap, group 4 demonstrated more bone formation on histomorphometric analysis at eight weeks (43.1%) than did group 3 (28.3%) (p < 0.01). Additionally, heterotopic bone formed outside the boundaries of the defect in eight of the fifteen animals in group 3, which had no periosteal flap. CONCLUSIONS: Bone-tissue engineering with use of the OPLA-HY matrix and rhBMP-2 produced good bone formation in the rat femoral defect model. However, the addition of a vascularized periosteal flap significantly increased bone formation within the boundaries of the defect and prevented heterotopic ossification.

Simultaneous toe-to-hand transfer and lower extremity amputations for severe upper and lower limb defects: the use of spare parts.

From 1995 to 2000, five microvascular toe-to-hand transfers were performed in three children who were simultaneously undergoing lower extremity amputations. Their ages at time of transfer ranged from 4 to 10 years and the types of lower extremity amputation included toe amputation, foot amputation and through-knee amputation. The resulting toe-to-hand transfers included three great toe-to-thumb transfers and one combined great and second toe-to-hand transfer. The toe-to-hand transfers were all successful and all the lower extremity amputations healed without complications. In all cases, improved hand function and lower extremity function was noted by the families. These unique cases represent the ultimate use of spare parts in congenital hand surgery.

Prefabrication of bone by use of a vascularized periosteal flap and bone morphogenetic protein.

The purpose of this pilot study was to prefabricate a vascularized bone graft by using a vascularized periosteal flap containing osteoprogenitor cells, a structural matrix, and recombinant human bone morphogenetic protein-2 (rhBMP-2). In a rat model, a periosteal flap vascularized by the saphenous artery and vein was dissected off the medial surface of the tibia. This flap consisted of three layers-periosteum, muscle, and fascia-and was tubed on itself to form a watertight chamber that was then transferred on its vascular pedicle to the groin. A total of 78 vascularized periosteal chambers were constructed in 39 animals and divided into 10 groups. In group 1, the periosteal chamber was left empty. Groups 2, 3, and 4 consisted of the periosteal flap and rhBMP-2, but in group 3, the proximal vascular pedicle was ligated, and in group 4, the flap was harvested without the periosteal layer and turned inside out. Groups 5 through 10 consisted of the vascularized periosteal flap containing several different structural matrices (calcium alginate spheres, polylactic acid, or demineralized bone matrix) with or without rhBMP-2. Animals were killed at 2, 4, or 8 weeks in each group. The presence and density of any new bone formation was evaluated both radiologically and histologically. Significant bone formation was seen only in those periosteal flaps containing rhBMP-2 and either the calcium alginate or polylactic acid matrix. New bone formation increased both radiologically and histologically from 2 weeks to 8 weeks only in the periosteal flaps containing the polylactic acid matrix and rhBMP-2. This preliminary study therefore suggests that four factors-blood supply, osteoprogenitor cells in the periosteal layer, a biodegradable matrix, and rhBMP-2-are required for optimal prefabrication of a vascularized bone graft.

Evaluation of an acute nerve compression injury with magnetic resonance neurography.

Although magnetic resonance (MR) imaging is performed routinely, current techniques offer little for evaluation of the peripheral nervous system. An animal model was developed to evaluate the appearance and geographic changes associated with an acute nerve compression injury by MR neurography. Several measurements of signal intensity were made for the contralateral noninjured nerve and each sciatic nerve proximal to the site of compression (PN), at the site of compression (CN), and distal to the site of compression (DN) injury. Mean (+/-SEM) values of the MR nerve/muscle signal intensity ratio were 2.24 +/- 0.08 for normal nerve, 2.29 +/- 0.12 for PN, 3.11 +/- 0.31 for CN, and 4.33 +/- 0.47 for DN. There was a statistically significant geographic variation of nerve/muscle signal intensity ratios along the course of the nerve relative to the site of injury that MR neurography could detect. Magnetic resonance neurography may have significant potential to provide more information about problems such as brachial plexus injuries and peripheral nerve compression.

Emergency microsurgical revascularization for critical ischemia during surgery for Dupuytren's contracture: a case report.

Injuries to the common digital or proper digital arteries during surgery for Dupuytren's contracture are relatively rare but may be underreported. Delay in recognition and inadequate management may result in prolonged ischemia or gangrene and eventually necessitate finger amputation. A patient who sustained inadvertent injury to several digital arteries during reoperation for recurrent Dupuytren's contracture of the ring and small fingers developed persistent critical ischemia of both fingers. He was transported emergently to a replantation center where the arterial injuries were immediately repaired by microsurgical techniques, resulting in successful salvage of both fingers.

Neonatal chest and abdominal radiation dosimetry: a comparison of two radiographic techniques.

Radiographs of the chest and the abdomen are the most commonly requested diagnostic X-ray examinations undertaken in neonatal intensive care units. Frequently, for a single child, both radiographs are requested simultaneously. These images can be obtained either as two separate exposures (one of the chest and one of the abdomen), or as a single exposure to include both anatomical regions on one film. This study compared the effective dose imparted as a result of each technique. A neonatal anthropomorphic phantom was designed and constructed, and each radiographic technique was simulated. Entrance surface dose (ESD) and dose-area product (DAP) were measured and estimates of effective dose were made from the DAP values. The mean effective dose for the separate exposure technique was estimated to be 37.3 microSv compared with 35.5 microSv for the combined exposure technique. However, observed variations in field size gave rise to uncertainties in DAP and thus the effective doses estimated from it. Hence, no significant difference in effective dose was observed between the radiographic techniques. The observed coefficient of variation in field size (16% for a 2.5 kg neonate) demonstrates that good standards of radiographic practice are more important than choice of technique.

Treatment of arthritis of the trapeziometacarpal joint with trapeziectomy and hematoma arthroplasty.

Trapezial excision is a simple and effective method of treating painful TM arthritis. Recent studies, as well as the authors' experience, suggest that the results of this procedure, in the short-term, provide equivalent pain relief compared with other, more complex techniques requiring tendon interposition and ligament reconstruction. Trapezial excision and hematoma arthroplasty is now the authors' procedure of choice for treating painful arthritis at the base of the thumb, regardless of Eaton stage. Long-term prospective comparison of trapezium excision alone and LRTI arthroplasty may help determine whether the additional strength gains accompanying the latter are associated with increased patient satisfaction, in high-demand patients.

Congenital constriction band syndrome causing ulnar nerve palsy: early diagnosis and surgical release with long-term follow-up.

Three children with congenital constriction band syndrome affecting their upper extremities demonstrated clinical and electrophysiologic signs of a complete ulnar nerve palsy. Two of the children were diagnosed immediately postpartum with the subtle findings of an intrinsic minus posture of their hand and inability to actively extend their fingers at the proximal interphalangeal joints. One child had at least 5.5 months of intrauterine compression of the ulnar nerve detected by ultrasound examination at 18 weeks. Despite early release of the constriction bands, at 3 months in 2 children and at 6 months in 1 child, the ulnar nerve palsies persisted for a mean follow-up period of 7 years. If clinical examination of an infant with constriction band syndrome is indicative of a complete ulnar nerve palsy, the constriction band should be released as early as possible. If surgical exploration reveals significant compression of the ulnar nerve, consideration should be given to excising the involved segment of nerve with immediate primary nerve repair or nerve grafting because even early release of the constriction band does not seem to result in neurologic improvement in long-term follow-up studies.

Postoperative monitoring of pediatric toe-to-hand transfers with differential pulse oximetry.

Twenty-three toe-to-hand transfers performed in 21 children were monitored after surgery using differential pulse oximetry for 4 to 12 days. Pulse rate recorded by the pulse oximetry monitored the patency of the arterial anastomosis, whereas oxygen saturation (SaO(2)) corresponded to the patency of the venous anastomosis; these were both compared with the systemic pulse rate and oxygen saturation recorded by a second control pulse oximeter probe attached to a contralateral finger or toe. All 23 toe transfers were ultimately successful, but 2 required re-exploration for anastomotic problems detected by the pulse oximeter. Based on this experience, the following criteria have been developed for the nursing and junior medical staff: if the arterial pulse of the toe transfer is lost completely or if the pulse rate differs significantly from the systemic pulse rate, measured by the second control pulse oximeter, thrombosis of the arterial anastomosis should be suspected. If the oxygen saturation of the toe transfer decreases below the oxygen saturation measured by the control pulse oximeter and this differential is sustained over a period of time, thrombosis of the venous anastomosis should be suspected. Differential pulse oximetry appears to be superior to temperature monitoring and percutaneous and laser Doppler monitoring and provides the most simple and continuous technique of noninvasive postoperative monitoring of toe-to-hand transfers in children requiring reconstruction of traumatic or congenital deformities.

Comparison of long-term immunosuppression for limb transplantation using cyclosporine, tacrolimus, and mycophenolate mofetil: implications for clinical composite tissue transplantation.

This study compared the efficacy of long-term intermittent immunosuppression in preventing the rejection of a limb transplant across the strongest histocompatibility barrier in ACI --> Lewis rats using the conventional immunosuppressive agent cyclosporine-A and the newer immunosuppressive agents FK-506 (tacrolimus) and RS-61443 (mycophenolate mofetil). The recipient animals were immunosuppressed daily for 14 days postoperatively, followed by long-term intermittent, twice-weekly immunosuppression using cyclosporine 25 mg/kg, RS-61443 30 mg/kg, or FK-506 2 mg/kg. All three immunosuppressive agents were able to prolong the rejection of the skin component of a limb transplant compared with nonimmunosuppressed controls. Eight of nine animals receiving cyclosporine immunosuppression showed signs of rejection of the skin component of the limb transplant while continuing to receive long-term immunosuppression and had a mean rejection time of 61.6 days. Seven of 10 animals immunosuppressed with RS-61443 also showed signs of rejection while still receiving immunosuppression, with a mean rejection time of 43.6 days. Nine of 10 animals receiving FK-506 immunosuppression showed no signs of skin rejection, but died of bacterial pneumonia between 273 and 334 days after transplantation, with a mean rejection time of 296.1 days. There was no statistically significant difference between intermittent immunosuppression with cyclosporine and RS-61443, but FK-506 was significantly superior to both cyclosporine and RS-61443. The implication of this study is that FK-506, but not cyclosporine or RS-61443, is probably the only single immunosuppressive agent capable of preventing rejection of the skin component of a composite tissue transplant. Combination immunosuppression with FK-506 and RS-61443, therefore, may be required to allow composite tissue transplantation to become a predictable clinical reality in the future.

The innervation of the triangular fibrocartilage complex: nitric acid maceration rediscovered.

Injury to the triangular fibrocartilage complex (TFCC) is frequently implicated in the etiology of ulnar-sided wrist pain. This study examines the nervous anatomy of the TFCC using a nitric acid maceration technique and attempts to correlate this information with known tear patterns. Ten fresh frozen cadaveric specimens were studied in detail. Gross dissection of each upper-extremity specimen included removal of all flexor and extensor tendons. After identification and labeling with permanent color of the ulnar nerve, dorsal sensory branch of the ulnar nerve, posterior interosseous nerve, anterior interosseous nerve, and median nerve, an en bloc excision of the distal radioulnar region was performed. Digestion of the soft tissue was performed with nitric acid at sequential concentrations of 50% and 33% for 9 of 10 specimens. The digestion was halted by immersing the specimen in a mixture of 10% formaldehyde and 1% glycerine. After removal of bone, the specimens were fixed in paraffin, sectioned, and stained with hematoxylin and eosin. Nine of the 10 specimens were studied microscopically to determine the contribution of the grossly identified nerves to each zone of the triangular fibrocartilage complex as defined by Palmer's classification of acute TFCC tears. The anterior interosseous, median, and superficial radial nerves did not contribute to the innervation of the TFCC. The intraarticular course of the peripheral nerves could not be defined in the one specimen that was not digested with nitric acid. Nitric acid maceration is a rediscovered technique for identifying the nervous anatomy of soft tissues. The study showed that the triangular fibrocartilage complex is innervated by branches of the posterior interosseous, ulnar, and dorsal sensory ulnar nerves in a fairly consistent manner. Improved treatment of TFCC tears may result from an enhanced understanding of the supporting structures' innervation and mechanical function.

[Heterotopic and orthotopic bone formation with a vascularized periosteal flap, a matrix and rh-BMP-2 (bone morphogenetic protein) in the rat model]. / Heterotope und orthotope Knochenbildung mit einem vaskularisierten Periostlappen, einer Matrix und rh-BMP-2 (bone morphogenetic protein) im Rattenmodell.

The purpose of this study was to construct a vascularized bone graft using the osteoinductive bone morphogenetic protein (rh-BMP-2), a polylactic acid matrix (OPLA/HY), and a vascularized periosteal flap containing osteoprogenitor cells ectopically in the groin or orthotopically in a femoral defect. In the Lewis rat, periosteal flaps were harvested from the medial surface of the tibia vascularized by the saphenous artery and vein and were transferred to the groin on its vascularized pedicle. Alternatively, the periosteal flap along its pedicle was transferred between the thigh muscles to be wrapped around a femoral defect of 1 cm. The animals were divided into 10 groups (82 animals). In group 1, the periosteal flap was left empty in the groin. Groups 2 and 3 consisted of the periosteal flap and 20 micrograms rh-BMP-2, but in group 3 the vascular pedicle was ligated proximally. In group 4 the flap was harvested without the periosteal layer and turned "inside out". Groups 5 and 6 consisted of the periosteal flap and the matrix OPLA/HY +/- 20 micrograms rh-BMP-2. In the femoral defect model, bone formation was studied using the matrix OPLA/HY alone (group 7) or combined with the vascularized periosteal flap (group 8), or in combination with OPLA/HY + BMP (group 9) or OPLA/HY + BMP + the periosteal flap (group 10). The presence and density of new bone formation in the groin and femoral defect were evaluated radiologically and histologically at 4 and 8 weeks. Good bone formation in the groin chamber (ectopic) was demonstrated in the periosteal flap + OPLA/HY + BMP group. In the femoral defects, good bone formation (orthotopic) was seen in the OPLA/HY + BMP + the periosteal flap groups. However, with the presence of a vascularized periosteal flap, more bone formation along the rim of the defect was observed. This study of ectopic bone formation in the groin and orthotopic bone formation in the femoral defect demonstrates that optimal bone formation requires four factors: BMP, a biodegradable matrix, osteoprogenitor cells, and blood supply. Potentially in the future, this technique could be used to reconstruct a bony defect or a nonunion by covering the involved area with a vascularized periosteal flap and a suitable matrix combined with BMP. Alternatively, a vascularized bone graft could be prefabricated at a distant site and then transferred microsurgically into a defect.

Coccidioidomycosis fungal infection in the hand mimicking a metacarpal enchondroma.

Coccidioidomycosis, an infection caused by the fungus Coccidioides immitis, rarely affects the hand, but we report an unusual case which mimicked the radiological appearance of an enchondroma in the metacarpal. Curettage and bone grafting in combination with long-term antifungal therapy are necessary for successful treatment of coccidioidomycosis of the hand.

Practical illustrations in tissue engineering: surgical considerations relevant to the implantation of osteoinductive devices.

This paper provides practical illustrations in the use of osteoinductive devices (biomaterial carriers coupled with osteoinductive morphogens) for bone tissue engineering. We discuss the considerations relative to the implantation of these devices that may induce tissues that are located outside the boundaries of the osteoinductive device as well as outside boundaries of the normal skeletal envelope. Five reports of osteoinductive devices generating such tissues are reviewed. Histologic and radiographic data from a sixth example are presented and compared with histologic and radiographic findings typical of two varieties of myositis ossificans. A theory is advanced that osteoinductive implants may induce ectopic tissues that resemble fibro-osseous pathologies. Finally characteristics of tissue-engineered bone graft substitutes that may contribute to development of these pathologies and device characteristics that may obviate these ectopic tissues are considered.