Biomedical subjects

M D Neel

Publications and source records attributed to M D Neel.

8 recordsLinked to original sources

PubMed2001

Clinical responses to bone marrow transplantation in children with severe osteogenesis imperfecta.

Preclinical models have shown that transplantation of marrow mesenchymal cells has the potential to correct inherited disorders of bone, cartilage, and muscle. The report describes clinical responses of the first children to undergo allogeneic bone marrow transplantation (BMT) for severe osteogenesis imperfecta (OI), a genetic disorder characterized by defective type I collagen, osteopenia, bone fragility, severe bony deformities, and growth retardation. Five children with severe OI were enrolled in a study of BMT from human leukocyte antigen (HLA)-compatible sibling donors. Linear growth, bone mineralization, and fracture rate were taken as measures of treatment response. The 3 children with documented donor osteoblast engraftment had a median 7.5-cm increase in body length (range, 6.5-8.0 cm) 6 months after transplantation compared with 1.25 cm (range, 1.0-1.5 cm) for age-matched control patients. These patients gained 21.0 to 65.3 g total body bone mineral content by 3 months after treatment or 45% to 77% of their baseline values. With extended follow-up, the patients' growth rates either slowed or reached a plateau phase. Bone mineral content continued to increase at a rate similar to that for weight-matched healthy children, even as growth rates declined. These results suggest that BMT from HLA-compatible donors may benefit children with severe OI. Further studies are needed to determine the full potential of this strategy.

Body Height↗

PubMed2001

Magnetic resonance imaging detection of avascular necrosis of the bone in children receiving intensive prednisone therapy for acute lymphoblastic leukemia or non-Hodgkin lymphoma.

The purpose of this study was to determine the frequency with which magnetic resonance (MR) imaging detects avascular necrosis of the bone (AVNB) in children with acute lymphoblastic leukemia (ALL) or advanced-stage non-Hodgkin lymphoma (NHL) who receive prednisone during remission induction, reinduction, and maintenance chemotherapy; to assess the clinical significance of these findings; and to identify factors predictive of AVNB. We prospectively obtained MR imaging of the hips and knees of 116 children who had completed at least 1 year of treatment for ALL or advanced-stage NHL on identical prednisone-containing regimens between December 1991 and October 1994. MR imaging findings of AVNB were compared with clinical outcomes, and the effect of therapeutic and patient factors on the frequency of AVNB was analyzed. The MR imaging findings of 17 of the 116 participating patients were consistent with AVNB. The most common clinical manifestation was joint pain (11 patients). Only one patient had progressive joint deterioration that necessitated surgical replacement. Only age 10 years or more at the time of the primary diagnosis was significantly associated with the development of AVNB (P = 0.004). MR imaging showed changes consistent with AVNB in approximately 15% of this patient population. However, most patients in this study who had MR imaging signs of AVNB did not experience progressive joint destruction, even with continued prednisone therapy. Therefore, the clinical usefulness of MR imaging as a screening tool for AVNB in this set of patients remains uncertain.

Adolescent↗

PubMed2001

Fractures in pediatric Ewing sarcoma.

PURPOSE: To determine the incidence, timing, and clinical significance of long-bone fractures in children with Ewing sarcoma family of tumors (ESFT). PATIENTS AND METHODS: We retrospectively reviewed 93 consecutive cases of ESFT of the long bones seen at a single institution over the course of a 37-year period. RESULTS: Fracture occurred in 14 (15%) of 93 patients with long-bone ESFT, most commonly in the femur. Approximately 30% of patients with tumors of the femur had fractures at some point in the course of their disease. The incidence of fracture was highest among patients with tumors of the proximal third of the femur (50%); these fractures were usually present at the time of initial diagnosis. Nine (64%) of the 14 fractures occurred after the start of radiotherapy, and three of these were associated with either local recurrence or second malignancy. CONCLUSIONS: Patients with femoral ESFT are at high-risk for fracture. If fractures occur after the completion of therapy, recurrence or second malignancy should be suspected.

Adolescent↗

PubMed2000

Brachytherapy for pediatric soft-tissue sarcoma.

PURPOSE: To review the use of brachytherapy (BRT) to treat soft-tissue sarcoma (STS) in pediatric patients at St. Jude Children's Research Hospital. METHODS AND MATERIALS: Thirty-one patients, median age 11 years (range 1-21 years) with Pediatric Oncology Group (POG) Grade 2-3 soft-tissue sarcoma (excluding rhabdomyosarcoma and Ewing's sarcoma) were treated with BRT initially (n = 27) or at the time of recurrence (n = 4) using I-125 or Ir-192 in a temporary (n = 29) or permanent implant (n = 2). Twelve patients were treated with BRT alone and the remaining 19 were treated with a combination of BRT and external beam irradiation (EBRT). The majority of patients had involved margins of resection (n = 20) and tumors less than 5 cm (n = 17). RESULTS: Twenty-seven patients were treated with BRT at the time of presentation. Among the 10 patients treated with BRT alone, one patient developed metastases (4 months) and died of metastatic disease (12 months after presentation); there were no local or regional failures among the remaining 9 patients. Among the 17 patients treated with a combination of BRT and EBRT, there was one local (17 months), two regional (both at 8 months), and 3 distant failures (12, 15, 66 months). The median survival for the surviving 25 patients was 34 months. Wound dehiscence, fibrosis/telangectasia, pigment changes, and cellulitis were the most common side effects. CONCLUSIONS: BRT is an excellent treatment option for pediatric patients with STS. Disease control may be achieved with a high rate of success when BRT is used alone or in combination with EBRT. BRT should be considered for patients with STS who require radiation therapy with the objective of reducing the dose to normal tissues and shortening the overall treatment time. Limb preservation, functional outcome, and toxicity assessment require careful assessment in a prospective study.

Adolescent↗

PubMed2000

Percutaneous radiofrequency ablation of osteoid osteoma.

Osteoid osteoma is a benign bone tumor. Patients usually require surgical treatment for reliable pain relief. Difficulties with intraoperative localization of the tumor and anatomic locations that carry a high morbidity with en bloc resection complicate open surgery. Various methods have been developed to lessen the invasiveness of surgery including computed tomography-guided percutaneous radiofrequency thermal ablation. Eleven patients in three different centers were evaluated and diagnosed with osteoid osteoma based on typical histories, physical examinations, and imaging studies. All patients were treated with computed tomography-guided percutaneous radiofrequency thermal ablation after medical treatment failed. Excellent pain relief was reported in 10 patients. One patient suffered recurrence of a femoral neck lesion despite an initial 7-month period without pain. Patients were given a questionnaire to quantify the effectiveness of percutaneous radiofrequency ablation in terms of pain relief and return to function. The current study shows that percutaneous radiofrequency thermal ablation provides reliable, excellent pain relief and early return to function with minimal morbidity as compared with traditional open techniques. The authors suggest that this technique be used for all patients with extraspinal osteoid osteomas that are not immediately adjacent to neurovascular structures.

Adolescent↗

PubMed1999

Extracortical bridging callus after limb salvage surgery about the knee.

The increasing survival of children treated for osteosarcoma has led to an increase in limb sparing surgery. Little published information is available about the postoperative imaging appearance of this technique. Thus, information gleaned from medical records and imaging reviews was correlated with clinical outcome of 19 consecutive children (median age at diagnosis, 12.3 years) treated for distal femoral osteosarcoma with a cemented rotating hinged knee endoprosthesis with porous coated collar. An extracortical bridging bony callus was identified in 16 patients who were followed up after surgery for a median of 2.8 years (range, 1.4-6 years). Extracortical bridging bony callus formation was circumferential in eight and preferentially posterior in nine, and ranged from 0.5 to 0.7 cm in thickness; 14 patients had lucent lines subjacent to the bridging bone. Thirteen patients had good functional use of the surgically treated leg. Five patients had progressive metastatic disease develop. One patient had local disease recurrence 8 months after surgery. Extracortical bridging bone was not identified in three patients, two of whom had infection develop 7 months and 17 months after surgery; both infections required amputation. Extracortical bridging bone preferentially develops posteriorly, along the compression side of the femur, often is associated with subjacent lucency, and seems to reflect increased prosthetic stability.

Adolescent↗

PubMedDate not supplied

Modular endoprostheses for children with malignant bone tumors.

BACKGROUND: The treatment of malignant bone tumors in skeletally immature patients is difficult because the required surgery removes the growth plate of one extremity. To date, few techniques for limb salvage have been successful due to complications involving limb expansion and limb-length discrepancy. Newer technology is now available for prosthetic replacements for modular expansion. METHODS: The authors review current surgical treatment of malignant bone tumors in children, with emphasis on reconstruction with expandable modular prostheses, and they present their own experience. RESULTS: Thirty-seven children with malignant bone tumors underwent primary tumor resection and reconstruction with a modular prosthetic device. Fourteen had subsequent successful expansions with modular prostheses. A new prosthesis, in which lengthening is achieved by an external electromagnetic field rather than an open surgical procedure, is discussed. CONCLUSIONS: Limb-preserving surgery in children with malignant bone tumors can be accomplished successfully with modern prosthetic devices that have expandable modules within them. The technique of expandable prostheses using electromagnetic fields rather than surgical interventions shows promise.

Bone Neoplasms↗

PubMedDate not supplied

The use of a closed expandable prosthesis for pediatric sarcomas.

PURPOSE: The purpose of this paper is to review our experience with a non-invasive expandable prosthesis for skeletally immature patients following limb-salvage for malignant tumors about the knee. MATERIALS & METHODS: Between 1998 and 2002, Repiphysis prostheses (Wright Medical Technology, Memphis, Tenn.) were implanted in 18 patients. 16 patients had at least 12 months follow-up. There were 10 males and 8 females. The diagnosis was Stage IIB osteosarcoma in all patients. Sites included femur 14, and 4 proximal tibias. The average age was 10.7 years (range 8-16); the average age for males was 12 years and females, 9 years. Fifteen of the prostheses were implanted at the time of surgical resection and the remainder was conversions of previous surgery. RESULTS: Follow-up averaged 24.8 months (range 12-47). Fourteen patients have undergone a total of 58 lengthening procedures. Average expansion 38 mm per patient (range, 10-76 mm). An average of 8.5 mm per lengthening procedure. There was only one failure to lengthen. ISOLS functional scores averaged 83.5%. For those with a current functional prosthesis, the ISOLS score averaged 94%. Three patients have reached maximal expansion and converted to a conventional prosthesis. There were complications in 7 patients: 2 expandable component fractures, 1 femoral component fracture, 2 stem fractures, 1 stem loosening and 1 deep infection. Of the two expandable component fractures, 1 patient reached full expansion and was converted to an endoprosthesis. The femoral component fracture and 2 stem fractures were revised to a new prosthesis 13 months post-op and are functioning well. The 1 loose stem was revised to an APC. CONCLUSIONS: The Repiphysis prosthesis utilizes energy stored in a spring that is held compressed by a locking mechanism. Controlled release of the locking mechanism via an external electromagnetic field allows for lengthening of the device. In our early experience, the functional results were excellent similar to conventional modular devices. Complications should be anticipated but are salvageable. This device allows limb salvage in pediatric patients when amputation would be otherwise chosen.

Adolescent↗