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Biomedical subjects

Neil F Jones

Publications and source records attributed to Neil F Jones.

At least 19 recordsLinked to original sources
PubMed2006

Temporary arteriovenous loop between the saphenous vein and the first plantar metatarsal artery in toe-to-hand transfers.

We describe a technique for creating a temporary arteriovenous loop by anastomosing the saphenous vein to the first plantar metatarsal artery to facilitate harvesting and subsequent anastomosis of a great or second toe transfer. This technique has been used in 9 patients: 6 pediatric toe-to-hand transfers for congenital hand differences and 3 adult toe transfers for a thumb amputation. All 9 toe transfers survived. The advantages of this technique are that it allows precise determination of the exact length of the loop to reach the recipient artery, it facilitates palmar positioning of the arterial pedicle, and, if necessary, the saphenous vein can be anastomosed directly to the lateral digital artery of a great toe transfer or the medial digital artery of a second toe transfer rather than the first plantar metatarsal artery itself, thereby minimizing more proximal dissection of the first plantar metatarsal artery, which is more difficult and time consuming.

Adult↗
PubMed2005

Sequential second free bone flaps for reconstruction of metachronous mandibular defects.

BACKGROUND: The purpose of this study was to identify patients who had previously undergone composite resection of a primary carcinoma of the oral cavity and immediate mandibular reconstruction with an osteocutaneous free flap and subsequently developed a local recurrence or a second metachronous tumor that required a second composite resection and immediate mandibular reconstruction with a second osteocutaneous free flap, in order to evaluate bone-to-bone healing of the two vascularized bone grafts and the long-term survival of these patients. METHODS: Five patients who had undergone composite resection of a primary carcinoma of the oral cavity subsequently developed a local recurrence or a second metachronous tumor and therefore underwent mandibular reconstruction with two sequential osteocutaneous free flaps. Two sequential fibular osteocutaneous flaps were performed in three patients, two sequential radial forearm osteocutaneous flaps in one patient, and a scapular osteocutaneous flap followed by a radial forearm osteocutaneous flap in one patient. End-to-end osteosynthesis of the second free vascularized bone graft to the first free vascularized bone graft was achieved using mandibular reconstruction plates, miniplates, or compression screws. RESULTS: All five patients achieved solid bone-to-bone healing of the second free vascularized bone graft to the first free vascularized graft. Despite two patients only surviving 4 months after the second mandibular reconstruction, one patient survived for 1 year and 8 months and two patients remain disease-free after more than 3 years. CONCLUSION: Stable bone-to-bone union of a second osteocutaneous free flap to a previous osteocutaneous free flap mandibular reconstruction improves the quality of life of those patients who require a second composite mandibular resection for the treatment of a local recurrence or a metachronous tumor, but it is probably only palliative.

Adult↗
PubMed2005

Pediatric upper extremity replantation.

The evolution of microsurgical technique has led to increasing success with pediatric replantation. The broader inclusion criteria for pediatric replantation, together with the greater technical demands of repair and the less favorable mechanism of pediatric amputations (crush-avulsion), yield a slightly lower overall survival rate than in adults. The superior nerve and soft tissue regenerative capacity of children appears to produce better functional outcomes. Nonetheless, the issue of cosmesis and developing self-image in a child may have ramifications beyond a simple calculus of range of motion and strength variables--hence the imperative that microsurgical salvage be attempted in pediatric upper-extremity amputations.

Amputation, Traumatic↗
PubMed2005

Healing of a scaphoid nonunion using human bone morphogenetic protein.

A chronic nonunion of a proximal pole fracture of the scaphoid was treated by curettage of the nonunion, single K-wire fixation, and implantation of 50 mg of human bone morphogenetic protein followed by 12 weeks of cast immobilization without any conventional corticocancellous bone grafting or rigid screw fixation. Radiographs showed signs of bony healing by 12 weeks and a magnetic resonance imaging scan 6 years after surgery showed no signs of avascular necrosis. The potential future applications of human bone morphogenetic protein in hand surgery are discussed.

Adolescent↗
PubMed2005

Iatrogenic arteriovenous fistula after revascularization of the hand.

This is the first report of an iatrogenic arteriovenous fistula complicating revascularization of an incomplete amputation of the hand, due to inadvertent anastomosis of the proximal radial artery to the distal cephalic vein. This resulted in a severely painful, massively swollen hand, which was initially diagnosed as an infection or poor venous outflow and eventually required a below-elbow amputation. This complication of replantation or revascularization should be preventable by carefully matching the thickness of the vessel wall and the diameter of the lumen, to avoid anastomosing a proximal artery to a distal vein.

Adult↗
PubMed2005

Successful replantation of the leg in a pre-ambulatory infant.

The authors report the first successful replantation of a below-knee amputation in a 7-month-old infant prior to the development of a standing and walking gait. Seven years following surgery, the child demonstrates excellent ankle and knee range of motion, has regained plantar sensation, and is able to walk, run, and jump without needing a brace. Despite a leg-length discrepancy of 5.5 cm, it is likely that future overgrowth of the injured limb will improve this discrepancy. This child has excellent potential for a successful functional outcome, given the very young age at the time of replantation and the plasticity of the central nervous system.

Accidents, Traffic↗
PubMed2005

Microdissection thinning of a pedicled deep inferior epigastric perforator flap for burn scar contracture of the groin: case report.

A severe burn scar contracture of the groin in a 25-year-old woman was successfully reconstructed with microdissection and thinning of a pedicled deep inferior epigastric perforator (DIEP) flap. This perforator flap is a relatively thin cutaneous flap, but may still require secondary defatting procedures, especially when used for coverage of mobile anatomic areas such as the groin and axilla. A deep inferior epigastric perforator flap was radically thinned by excising the subcutaneous fatty layer very carefully under loupe magnification, to preserve the subdermal vascular plexus. One year after surgery, the patient can abduct and rotate the hip freely without limitation.

Adult↗
PubMed2005

Temporary fixation with the Agee-Wristjack during correctional osteotomies for malunions and nonunions of the distal radius.

Upper extremity surgeons are often responsible for managing complex malunions and nonunions of distal radius fractures. Studies have demonstrated that corrective osteotomies of the malunited distal radius with placement of sculpted bone grafts produce the best functional and cosmetic results in patients. We describe a technique for providing provisional stabilization of the osteotomy site for treatment of distal radius malunions and nonunions using the Agee-Wristjack external fixator device. The Agee-Wristjack has several features that make it superior to other available small external fixators. Its gear mechanisms confer stable distraction of the distal radius following osteotomy and greatly facilitate appropriate positioning of the distal fragment. Iliac crest bone graft may be harvested and shaped precisely to fit the osteotomy defect. Placement of the Agee-Wristjack's distal fixator pins into the index metacarpal instead of the distal radius fragment facilitates application of a plate, with minimal interference from the distal pins. Finally, the Agee-Wristjack may be maintained following surgery to supplement the internal fixation.

Contraindications↗
PubMed2005

The reverse radial forearm flap for soft tissue reconstruction of the wrist and hand.

Soft tissue defects of the upper extremity must be carefully assessed to determine the most appropriate method of coverage. Direct closure and local flaps represent the most basic techniques on the reconstructive ladder; however, they are inadequate for large or complex defects. Split thickness skin grafts are appropriate for granulating wounds with a bed of vascularized tissue; however, if there is an exposed joint or bone devoid of periosteum or tendon devoid of paratenon, there will be insufficient neovascularization, and the graft will inevitably fail. The reconstructive hand surgeon must then pursue more complicated techniques for wound coverage based upon knowledge of the available pedicled and free flaps. The reverse radial forearm flap potentially offers thin, mobile skin with similar characteristics to the skin over the dorsum of the hand. This flap is more versatile than the groin flap and probably more reliable than the posterior interosseous artery flap for coverage of moderate-sized defects of the dorsal or palmar wrist and hand and is specifically indicated for coverage of degloving injuries of the dorsal wrist and hand, after release of thumb-index finger web space, and for coverage of amputations of the thumb in preparation for toe-to-thumb transfer.

Contraindications↗
PubMed2004

Hand surgery in organ transplant patients.

PURPOSE: This study presents a series of organ transplant patients who developed problems that affected their upper extremities, related to the organ transplant operation itself, to the patient's underlying systemic disease, to long-term immunosuppression, or to subsequent hand injury after the organ transplant surgery. METHODS: A retrospective chart review of 40 organ transplant patients with upper extremity problems at 3 major organ transplant centers was performed. RESULTS: Six general problems were identified that affected the hand and upper extremity in these transplant patients: inflammatory conditions (16), nerve compression syndromes (18), infections (6), neoplasms (6), vascular problems (4), and trauma (14). Thirty-eight patients had 72 separate hand procedures. No problems were encountered with postoperative infections, and skin and bony healing occurred uneventfully. CONCLUSIONS: Organ transplant patients are prone to developing atypical infections, skin malignancies, ischemia, and various nerve compression syndromes that affect the hand. These patients with upper-extremity problems should be treated in a manner similar to any patient without prior organ transplant.

Bursitis↗
PubMed2004

Cleft hands with six metacarpals.

PURPOSE: The purpose of this study was to identify children with cleft hands whose radiographs showed metacarpal polydactyly with 6 metacarpals to support the hypothesis that cleft hand develops not as a result of a longitudinal failure of formation but through a process of central polydactyly and osseous syndactyly. METHODS: We screened the hand radiographs of all children with a transverse or longitudinal deficiency of the upper limb and identified 8 children with cleft hands containing 6 metacarpals. RESULTS: Six cleft hands had a missing middle finger and consisted of a thumb and index finger separated from the ring and small fingers by a V-shaped central cleft. Two children had a more severe form of cleft hand with absence of both the index and middle fingers but presence of 6 metacarpals. CONCLUSIONS: These 8 cleft hands containing 6 metacarpals showed progression of polydactyly of the middle finger and osseous syndactyly between the 2 middle finger metacarpals and the adjacent index and ring finger metacarpals. This contradicts a longitudinal failure of formation mechanism and supports the alternative hypothesis that cleft hand, polydactyly, and syndactyly develop through a similar teratogenic mechanism. The 2 cleft hands that had more severe suppression of the index and middle fingers yet had 6 metacarpal polydactyly provided confirmatory evidence that both typical cleft hands and the more severe manifestations of cleft hand with absence of multiple digits develop through a similar failure of induction mechanism.

Child↗
PubMed2004

Chondrogenic potential of multipotential cells from human adipose tissue.

The use of stem cells for cell-based tissue-engineering strategies represents a promising alternative for the repair of cartilaginous defects. The multilineage potential of a population of putative mesodermal stem cells obtained from human lipoaspirates, termed processed lipoaspirate cells, was previously characterized. The chondrogenic potential of those cells was confirmed with a combination of histological and molecular approaches. Processed lipoaspirate cells under high-density micromass culture conditions, supplemented with transforming growth factor-beta1, insulin, transferrin, and ascorbic acid, formed well-defined nodules within 48 hours of induction and expressed the cartilaginous markers collagen type II, chondroitin-4-sulfate, and keratan sulfate. Reverse transcription polymerase chain reaction analysis confirmed the expression of collagen type II and the cartilage-specific proteoglycan aggrecan. In summary, human adipose tissue may represent a novel plentiful source of multipotential stem cells capable of undergoing chondrogenesis in vitro.

Adipose Tissue↗
PubMed2003

Optimization of Schwann cell adhesion in response to shear stress in an in vitro model for peripheral nerve tissue engineering.

The design of nerve guidance channels (NGCs) is evolving to produce a favorable environment for neural regeneration. We created an in vitro model to evaluate the interactions between three centrally important components of this altered host environment: (1). Schwann cells, (2). substrate, and (3). sustained mechanical stimulus in the form of shear stress with laminar fluid flow. Preconfluent Schwann cells were plated on slides coated either with laminin, poly-D-lysine, type IV collagen, or fibronectin. These slides were placed into custom-designed, parallel-plate, flow chambers and were administered laminar fluid flow at a rate of 15 mL/min for 2 h. Schwann cell adhesion assays demonstrated that laminin (mean, 86.1%; SEM, 4.47%) and fibronectin (mean, 81.7%; SEM, 3.24%) were statistically superior to collagen type IV (mean, 57.7%; SEM, 3.96%) and poly-D-lysine (mean, 58.0%; SEM, 4.97%) (p < 0.001). Fibronectin (mean, 12.20%; SEM, 0.374%) induced statistically greater Schwann cell proliferation than did laminin (mean, 8.14%; SEM, 0.682%) (p < 0.001). Therefore, we recommend that fibronectin should be used as an important component of NGCs with further in vivo studies. As mechanical stress is an integral part of the host environment, our study is the first to incorporate this factor into an in vitro model for peripheral nerve tissue engineering.

Animals↗
PubMed2003

Reconstruction of composite through-and-through mandibular defects with a double-skin paddle fibular osteocutaneous flap.

Microsurgical reconstruction of composite through-and-through defects of the oral cavity involving mucosa, bone, and external skin has often required two free flaps or double-skin paddle scapular or radial forearm flaps for successful functional and aesthetic outcomes. A safe, reliable technique using a double-skin paddle fibular osteocutaneous flap to restore the intraoral lining, mandibular bone, and external skin is described. A large elliptical or rectangular skin paddle is designed 90 degrees to the longitudinal axis of the fibula, over the junction of the middle and distal thirds of the lower leg, based only on the posterolateral septocutaneous perforators. This skin flap can be draped anteriorly and posteriorly over the fibular bone to reconstruct both the intraoral defect and the external skin defect. The area between the two skin islands of the intraoral flap and the external flap is deepithelialized and left as a dermal bridge between the two skin islands, as opposed to the creation of two separate vertical skin paddles, each based on a septocutaneous perforator. The transverse dimension of the flap can be as great as 14 cm, extending to within 1 to 2 cm of the tibial crest anteriorly and as far as the midline posteriorly, and with a length of up to 26 cm, this flap should be more than sufficient for reconstruction of most through-and-through defects. This technique has allowed the successful reconstruction of large composite defects, with missing intraoral lining, mandibular bone, and external skin, for 16 patients, with 100 percent survival of both skin islands in all cases and without the development of any orocutaneous fistulae.

Adult↗
PubMed2002

Long-term viability of articular cartilage after microsurgical whole-joint transplantation and immunosuppression with rapamycin, mycophenolate mofetil, and tacrolimus.

The survival or rejection of articular cartilage in heterotopic vascularized joint transplants in rats immunosuppressed with rapamycin (SDZ RAD), mycophenolate mofetil (MMF), and tacrolimus was evaluated histologically up to 1 year after surgery. The vascularized knee joint of an ACI donor rat was transplanted to the groin of a Lewis recipient rat. Nonimmunosuppressed allografts were evaluated after 6 weeks and 3 months, and immunosuppressed allografts and control isografts were evaluated after 6 weeks, 3 months, 6 months, and 1 year. No rejection was seen in the control isografts. All allografts without immunosuppression were rejected at 6 weeks and 3 months. Eighteen of 21 knee joint transplants immunosuppressed with SDZ RAD and 17 of 22 knee joint transplants immunosuppressed with MMF were rejected between 6 weeks and 1 year. SDZ RAD and MMF caused significant side effects including compromised wound healing and bone marrow suppression culminating in weight loss and death. Eighteen of 19 knee joints immunosuppressed with tacrolimus showed no signs of rejection up to 1 year after surgery. Long-term intermittent immunosuppression with tacrolimus was significantly superior to SDZ RAD and MMF in preventing rejection of the transplanted articular cartilage of a vascularized knee joint allograft up to 1 year after surgery.

Animals↗
PubMed2002

Concerns about human hand transplantation in the 21st century.

The decision to perform a human hand transplant was justified perhaps on less than an ideal scientific basis-only approximately 60 rat limb transplants and 2 primate limb transplants have survived for longer than 200 days and only 8 of 19 pig limb osteomyocutaneous transplants showed no signs of rejection at 90 days. It seems unlikely that the survival of a human hand transplant will be any better than the survival of a kidney transplant, which has a half-life of approximately 7.5 to 9.5 years. Fourteen hand transplants, however, have now been performed in 11 humans with the skin component of 1 remaining viable up to 3 years after surgery. Intermittent episodes of acute rejection seem to have been relatively simple to reverse by temporarily increasing the dose of immunosuppressive agents and steroids. Chronic rejection has occurred in 1 patient, necessitating re-amputation of the transplanted hand. Active range of motion of the digits has been surprisingly better than would have been expected based on previous results of replantation, but return of sensibility has been less than optimal. The immunosuppression has been well tolerated without any major medical problems or life-threatening episodes, but some patients have developed chronic viral and fungal infections and several have developed posttransplant diabetes. Extrapolating from the previous experience of solid-organ transplants, chronic immunosuppression may predispose a hand transplant patient to an 80% chance of developing an infection, a 20% potential risk of developing posttransplant diabetes, and a 4% to 18% potential risk of developing a malignancy. Even though there is universal agreement that composite tissue allograft transplantation will become the ultimate reconstructive option, no one can predict the eventual role of hand transplantation in the future, but perhaps an international database of these hand transplant patients should be established so that independent reviewers can more objectively evaluate their functional outcome, the incidence of chronic rejection, and the risks of long-term immunosuppression.

Amputation, Traumatic↗