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Biomedical subjects

F H Sim

Publications and source records attributed to F H Sim.

At least 19 recordsLinked to original sources
PubMed2006

Does the method of treatment affect the outcome in soft-tissue sarcomas of the adductor compartment?

We have investigated the significance of the method of treatment on the oncological and functional outcomes and on the complications in 184 patients with soft-tissue sarcomas of the adductor compartment managed at three international centres. The overall survival at five years was 65% and was related to the grade at diagnosis and the size of the tumour. There was no difference in overall survival between the three centres. There was, however, a significant difference in local control with a rate of 28% in Centre 1 compared with 10% in Centre 2 and 5% in Centre 3. The overall mean functional score using the Toronto Extremity Salvage Score in 70 patients was 77% but was significantly worse in patients with wound complications or high-grade tumours. The scores were not affected by the timing of radiotherapy or the use of muscle flaps. This large series of soft-tissue sarcomas of the adductor compartment has shown that factors influencing survival do not vary across the international boundaries studied, but that methods of treatment affect complications, local recurrence and function.

Adolescent↗
PubMed2005

Intravascular extension of an osteosarcoma of the pubic bone into periprostatic venous plexus.

Pelvic osteosarcomas are uncommon but aggressive tumors that can invade the vascular system. We report a case of a 33-year-old man who presented with groin pain and was found to have a chondroblastic osteosarcoma invading the periprostatic venous plexus. Meticulous intraoperative exploration of the pelvis is necessary in such cases to resect tumor completely, thereby maximizing local control and preventing embolic complications.

Adult↗
PubMed2004

Rotationplasty about the knee: surgical technique and anatomical considerations.

Rotationplasty is an intercalary resection of a bone segment with subsequent reconstruction of the lower limb by rotating it through an arc of 180 degrees. After rotation, the rotated ankle functions as a knee joint, thereby powering a custom-made below-knee prosthesis. Rotationplasty is a satisfactory treatment option in selected patients. A prerequisite for this type of surgery is an intact sciatic nerve. Rotationplasty is indicated for skeletally immature patients with a tumoral lesion about the knee (<8-10 years of age), for older patients with large lesions that are not candidates for limb salvage as an alternative to above-knee amputation, and as a salvage procedure for chronically infected prosthetic implants. Preoperative planning includes the prediction of the exact remaining bone growth, because the ipsilateral distal tibial epiphysis will not completely substitute for the growth deficit resulting from the resected distal femoral and proximal tibial epiphyses. Therefore, minimal over length of the ankle of the operated leg is retained. Technical details of the surgery are described with particular emphasis on anatomical considerations. It provides a durable and biologic reconstruction and allows patients to become good functional below-knee prosthesis users and allows participation in recreational activities and sports.

Arthroplasty, Replacement, Knee↗
PubMed2001

Primary mixed tumor of bone.

Mixed tumors occur most commonly in major salivary glands. They may rarely appear in other sites, such as skin, breast, and lung. There have been rare reports of similar tumors occurring in bone. We report on a patient with a primary mixed tumor of bone. No other primary site has become apparent on follow-up of 5 years. Although mixed tumors detected by bone biopsy are likely to be metastatic, they may rarely represent primary bone neoplasms.

Adult↗
PubMed2001

Ewing's sarcoma: presentation and management.

Great strides have been made in the diagnosis and treatment of patients with Ewing's sarcoma. With the advent of modern chemotherapy, the long-term survival has improved to approximately 70%. Standard treatment for local control of the primary lesion has, historically, been chemotherapy and radiation. Currently, surgical resection has become a more effective option in the multidisciplinary treatment of patients with this disease. These current concepts and developments in the presentation and management of Ewing's sarcoma are discussed.

Bone Neoplasms↗
PubMed2001

Total knee arthroplasty after ipsilateral peripheral arterial bypass graft: acute arterial occlusion is a risk with or without tourniquet use.

A retrospective review was done of the total joint registry at the Mayo Clinic, Rochester, Minnesota, which contains the computerized records of 19,808 consecutive total knee arthroplasties (TKAs) including primary and revision that were performed from 1970 to 1997. From that database, 9 patients were found to have had a TKA after an ipsilateral peripheral arterial reconstruction. One patient had had bilateral peripheral arterial reconstruction followed by bilateral TKA, and 10 TKAs were reviewed. The medical records were reviewed retrospectively with particular attention given to the type of peripheral bypass surgery performed, the bypass graft source, the timing of the bypass surgery relative to TKA, the use of a tourniquet at the time of TKA, and the occurrence of complications after TKA. Of the 10 TKAs, 2 patients had acute arterial occlusion. One patient had a tourniquet, and the other patient did not. There was not a statistical correlation between graft type, tourniquet use, timing of surgery, postoperative anticoagulation, and occurrence of arterial occlusion. There is a marked risk of acute thrombosis of an ipsilateral arterial bypass graft after TKA that cannot be eliminated by performing the TKA without a tourniquet. Careful monitoring of the vascular status of the limb is required in the early postoperative period to detect arterial compromise. Should limb ischemia be suspected, an emergent vascular surgery consultation is required, and arterial flow to the lower extremity must be re-established.

Aged↗
PubMed2001

Is radiotherapy important for low-grade soft tissue sarcoma of the extremity?

Radiotherapy and limb-preserving surgery has replaced amputation and compartmental resection for treatment of soft tissue sarcomas. However, the role of radiotherapy in low-grade tumors remains unclear. This study reviews the outcomes of 132 patients who received multimodality treatment for low-grade soft tissue sarcoma. Large primary tumors (> 5 cm) and the absence of radiotherapy correlated with local recurrence. Radiotherapy was most effective in patients operated on with marginal margins. Patients who were treated with wide surgical margins or had small tumors (< or =5 cm) showed no benefit with adjuvant radiotherapy. Size greater than 5 cm and local recurrence correlated with metastasis. Radiotherapy appears to be important in the management of low-grade soft tissue sarcoma. The principles of local treatment for low-grade soft tissue sarcoma should be the same as for high-grade tumors with a combination of surgery and adjuvant radiotherapy. In a subset of patients with small and widely excised tumors, consideration may be given to withholding radiotherapy. Local recurrence and metastasis from low-grade soft tissue sarcoma may occur as long as 1 decade after primary tumor resection. Long-term review of patients with low-grade tumors may be indicated.

Adolescent↗
PubMed2001

The kinematic rotating hinge prosthesis for complex knee arthroplasty.

Fifty-eight patients (69 knees) treated with the Kinematic Rotating Hinged knee prosthesis for complex primary and salvage revision total knee arthroplasty were followed up for an average of 75.2 months (range, 24-199 months). The indications for use of the Kinematic Rotating Hinged knee prosthesis included severe bone loss combined with ligamentous instability (30 knees), nonunion of a periprosthetic fracture (10 knees), an acute periprosthetic fracture (nine knees), severe collateral ligamentous instability (five knees), reimplantation for infection (six knees), nonunion of a supracondylar femoral fracture (four knees), congenital dislocation of the knee (three knees), and treatment of a severely comminuted distal femur (two knees). At the time of surgery, the average patient age was 72 years (range, 46-92 years). Preoperatively, knee extension averaged 4.94 degrees (range, 0 degrees-40 degrees) and flexion averaged 81 degrees (range, 15 degrees-125 degrees). At final followup, knee extension averaged 1.25 degrees (range, -5 degrees-25 degrees) and flexion averaged 94.2 degrees (range, 5 degrees-125 degrees). The preoperative Knee Society Knee score averaged 40.3 points (range, 2-93 points) and improved to 77 points (range, 33-99 points) at final followup. Complications were numerous: 23 (32%) patients experienced at least one complication and 12 (17%) patients had two or more complications. Deep periprosthetic infection was the most common complication (14.5%), followed by patellar complications (13%), and prosthetic component breakage (10%). During the period of this study, there were 15,798 primary and 2673 revision total knee arthroplasties done at the authors' institution. The patients receiving a Kinematic Rotating Hinged knee prosthesis represent a highly complex and small subset (0.37%) of the overall population having knee arthroplasty. Although the use of the Kinematic Rotating Hinged knee prosthesis for these limited indications has been useful for the authors, the incidence of complications and the poor outcome of these complications is disconcerting. Hinged total knee arthroplasty should be reserved for the final salvage option of the treatment options available when doing complex primary and salvage revision knee arthroplasties.

Aged↗
PubMed2001

Treatment of aneurysmal bone cysts of the pelvis and sacrum.

BACKGROUND: Aneurysmal bone cysts are benign, non-neoplastic, highly vascular bone lesions. The purpose of this study was to describe the prevalence, the clinical presentation, and the recurrence rate of aneurysmal bone cysts of the pelvis and sacrum and to examine the diagnostic and therapeutic options and prognosis for patients with this condition. METHODS: Forty consecutive patients with an aneurysmal bone cyst of the pelvis and/or sacrum were treated from 1921 to 1996. Their medical records and radiographic and imaging studies were reviewed, and histological sections from the cysts were examined. Seventeen lesions were iliosacral, sixteen were acetabular, and seven were ischiopubic. Seven involved the hip joint, and two involved the sacroiliac joint. All twelve sacral lesions extended to more than one sacral segment and were associated with neurological signs and symptoms. Destructive acetabular lesions were associated with pathological fracture in five patients and with medial migration of the femoral head, hip subluxation, and hip dislocation in one patient each. The mean duration of follow-up was thirteen years (range, three to fifty-three years). RESULTS: Thirty-five patients who were initially treated for a primary lesion had surgical treatment (twenty-one had excision-curettage and fourteen had intralesional excision); two patients also had adjuvant radiation therapy. Of the thirty-five patients, five (14%) had a local recurrence noted less than eighteen months after the operation. Of five patients initially treated for a recurrent lesion, one had a local recurrence. At the latest follow-up examination, all forty patients were disease-free and twenty-eight (70%) were asymptomatic. There were two deep infections. CONCLUSION: Aneurysmal bone cysts of the pelvis and sacrum are usually aggressive lesions associated with substantial bone destruction, pathological fractures, and local recurrence. Current management recommendations include preoperative selective arterial embolization, excision-curettage, and bone-grafting.

Adolescent↗
PubMed2001

Chondrosarcoma of the pelvis. A review of sixty-four cases.

BACKGROUND: Treatment of pelvic chondrosarcoma is a difficult problem for the musculoskeletal oncologist. Poor rates of survival and high rates of local recurrence after surgical treatment have been reported in previous studies. The present study was designed to review the long-term oncologic and functional outcomes of surgical management in a large series of patients with pelvic chondrosarcoma who were treated at a single institution. METHODS: The cases of sixty-four patients with localized pelvic chondrosarcoma that had been surgically treated between 1975 and 1996 were reviewed retrospectively. The study was limited to patients who had received no previous treatment for chondrosarcoma. There were forty-one male and twenty-three female patients who had a mean age of forty-seven years (range, fifteen to eighty-eight years). The patients were followed for a minimum of three years or until death. The median duration of follow-up of the living patients was 140 months (range, thirty-nine to 295 months). RESULTS: Thirty-three of the sixty-four patients were first seen with grade-1 chondrosarcoma; twenty-three, with grade-2; one, with grade-3; and seven, with grade-4 (dedifferentiated chondrosarcoma). Thirteen patients had a hemipelvectomy to achieve local tumor control, whereas fifty-one patients underwent a limb-salvage procedure. Twelve patients (19%) had local recurrence, and eleven (17%) had distant metastases. At the time of the final follow-up, forty-four patients (69%) were alive without evidence of disease, thirteen (20%) had died of the disease, six (9%) had died of unrelated causes, and one (2%) was alive with disease. Less than a wide surgical margin correlated with local recurrence (p = 0.014). High-grade tumors correlated with poor overall survival (p < 0.001). All patients who had a limb-salvage procedure were able to walk at the time of the final follow-up, and they had a mean functional score of 77%, according to the system of the Musculoskeletal Tumor Society. CONCLUSIONS: Aggressive surgical resection of pelvic chondrosarcoma results in long-term survival of the majority of patients. There is a high correlation between tumor grade and overall or disease-free survival.

Adolescent↗
PubMed2000

Clinicopathologic features and treatment of postirradiation sarcoma of bone and soft tissue.

BACKGROUND AND OBJECTIVES: An analysis of the clinicopathologic features and treatment of patients with postirradiation sarcoma of bone and soft tissue was performed to guide modern evaluation and management. METHODS: A retrospective analysis of 135 sarcomas in 130 patients was performed. RESULTS: The mean age of the 130 patients was 48 years, and there was a female predominance because of irradiation for carcinomas of the breast and uterus. Indication for irradiation was a soft tissue lesion (such as lymphoma or breast cancer) in 58.5% of patients and a bone lesion (such as giant cell tumor or fibrous dysplasia) in 41.5%. The latent period (interval between irradiation and discovery of the sarcoma) ranged from 4-55 years (mean, 17 years). Of the lesions, 74% were stage IIB (high-grade extra-compartmental) and 24% were stage III (metastases). Ninety-four patients received their treatment at our institution. Of the 61 patients with resectable disease, 49 had amputations and 12 had limb salvage procedures. The 5-year cumulative survival rate was 68.2% for patients with peripheral (extremities, including proximal femur and hip) resectable lesions and 27.3% for patients with central (pelvis, head/neck, and ribs) resectable lesions. The local recurrence rate correlated with the surgical margin achieved: intralesional, 73%, marginal, 64%, and wide, 23%. CONCLUSIONS: The prognosis for patients with peripheral resectable postirradiation sarcomas is good if a wide surgical margin can be achieved. This group of patients should be treated aggressively because they have a new cancer.

Adolescent↗
PubMed2000

Surgical management of desmoid tumors of the female pelvis.

BACKGROUND: Desmoid tumors are neoplasms characterized by proliferation of fibroblasts without cytologic features of malignancy. Although desmoid tumors are not uncommon, pelvic desmoid tumors are rare and therapeutically challenging. We describe the surgical management of seven patients with histologically confirmed desmoid tumors arising in the pelvis. STUDY DESIGN: All patients, six with primary and one with recurrent desmoid tumors of the female pelvis, were treated at Mayo Clinic Rochester between 1976 and 1997. The mean age of one African-American and six Caucasian patients was 29.8 years (range 17 to 59 years). No history of previous relevant pelvic trauma was identified; six patients experienced pelvic or leg pain (or both). All patients presented with isolated masses; five of seven were located left of the midline, generally involving the obturator internis or levator muscles (or both). The surgical approach was transabdominal, with a vaginal component in one patient. In addition to this retrospective review of these seven patients, literature addressing the management of desmoid tumors of the female pelvis is reviewed. RESULTS: Extirpative surgery necessitated resection of musculoskeletal, vascular, or adjacent soft tissue structures. Mean tumor diameter was 13.9cm (range 5 to 27 cm). Although the median recorded blood loss was 1,425mL, one patient who refused blood products died secondary to surgical hemorrhage. The median followup for the remaining evaluable patients was 57 months (range 13 to 249 months). Recurrent disease developed in 3 of 6 patients at 3, 11, and 13 months after surgical resection and was successfully managed with subsequent reoperations, with or without adjuvant radiotherapy. CONCLUSIONS: Although recent reports demonstrate selective regression of desmoid tumors with antiestrogen therapy, management of symptomatic pelvic desmoid tumors in young women may necessitate an operation. In our series, all primary and recurrent tumors were managed with resection of involved bone and other adjacent soft tissues. The role of adjunctive radiotherapy or hormonal therapy remains to be defined.

Adolescent↗
PubMed2000

Large tumor endoprostheses and extracortical bone-bridging: 28 patients followed 10-20 years.

Aseptic loosening is a common cause of failure in large tumor endoprostheses. The concept of extracortical bone-bridging was developed to tackle the problem of loosening. New bone which forms across the junction of the bone-prosthesis junction is believed to improve fixation by controlling the transfer of stresses across the junction as well as by giving additional stability to the prosthesis. We present the long-term experience with this concept following major reconstruction after tumor and non-tumor conditions in 31 patients. The overall function was good for upper and lower limb prostheses. Most patients had extracortical bone bridging which was maintained for over 10 years. In 1/3 of patients this involved over 75% of the prosthetic circumference. Prosthetic survival was best with intercalary devices, followed by proximal femoral and distal femoral prostheses. Survival of prostheses in young active patients was similar to that reported in older patients undergoing primary joint replacement.

Adolescent↗
PubMed2000

Dedifferentiated clear cell chondrosarcoma.

Dedifferentiation, a change in the histologic character and clinical behavior of a tumor to a more immature and aggressive one, occurs in approximately 11% of all chondrosarcomas. The original lesion is usually a low-grade chondrosarcoma. Clear cell chondrosarcoma is a rare cartilaginous tumor of low-grade malignancy with a preference for the ends of long bones. It is usually curable by resection. Recurrence commonly follows inadequate surgery, and metastases to lung, brain, and bones can develop. However, dedifferentiation has not yet been described in association with clear cell chondrosarcoma. Three patients are described who were initially diagnosed as having clear cell chondrosarcoma of the femur. Two were treated with en bloc resection for a clear cell chondrosarcoma. One of these had an undifferentiated sarcoma in a local recurrence after 6 years. In the second, metastasis of the clear cell chondrosarcoma developed 5(1/2) years after surgery; autopsy revealed undifferentiated sarcoma in the lung, heart, and lumbar spine. The third patient had dedifferentiated clear cell chondrosarcoma at the time of resection following the biopsy diagnosis of clear cell chondrosarcoma. All three died with metastatic disease. These three patients represent three different manifestations of dedifferentiation-at initial diagnosis, at recurrence, and at metastasis. To our knowledge, this is the first description of dedifferentiation occurring in clear cell chondrosarcoma.

Adenocarcinoma, Clear Cell↗
PubMed2000

Sacropelvic resection for recurrent anorectal cancer. A multidisciplinary approach.

A multimodal approach including preoperative external beam radiation, surgical resection, and intraoperative electron radiation was used in 23 patients with locally advanced anal or recurrent rectal cancers involving the sacrum. The proximal extent of complete sacral resection was S2 in three patients, S3 in 12 patients, S4 in two patients, and S5 in one patient. The tumor was confined to the anterior sacral cortex in five patients. The resection was marginal in 10, contaminated marginal in 11, and intralesional in two patients. At 19 to 54 months of followup, five patients are alive without evidence of disease and four are alive with disease. Twelve patients died of their disease, and two died of other causes. There was a mean survival of 32.9 months for the patients who were alive at followup. Kaplan-Meier survival for all patients was 82% at 1 year and 73% at 2 years, with death of disease as an endpoint. Thirteen (57%) patients had another local recurrence develop at a mean of 17.2 months. Eight (35%) patients had metastatic disease develop at a mean of 16.3 months. Proper patients selection is important in ensuring a favorable outcome from this aggressive surgery.

Adenocarcinoma↗
PubMed2000

Vascularized free fibular transfer combined with autografting for the management of fracture nonunions associated with radiation therapy.

BACKGROUND: The purpose of this study was to evaluate the functional results, rates of union, and complications associated with vascularized free fibular transfer combined with autografting for the treatment of nonunions in previously irradiated bone. METHODS: Seventeen patients who had had eighteen vascularized free fibular transfers combined with autografting for the treatment of nonunion of a fracture in previously irradiated bone were included in this study. There were eleven female patients and six male patients. Eight patients had a bone neoplasm and nine, a soft-tissue neoplasm. The diagnosis was Ewing sarcoma in four patients; lymphoma, malignant fibrous histiocytoma, and rhabdomyosarcoma in two patients each; and cavernous hemangioma, metastatic breast carcinoma, reticulum-cell sarcoma, myxosarcoma, hemangiopericytoma, and fibrosarcoma in one patient each. The remaining patient had a soft-tissue tumor for which the diagnosis was not known. All patients received radiation therapy. The average dose was 5564 centigray. There were no recurrent tumors. The average interval between the radiation therapy and the original fracture was 111 months. The fracture was in the femur in thirteen patients, in the humerus in three, and in the tibia in one. All patients had operative or nonoperative treatment, or both, of the initial fracture, and two had iliac-crest bone-grafting after the initial open reduction and internal fixation procedure. The ages of the patients ranged from thirteen to eighty-two years at the time of the vascularized free fibular transfer. All fibular transfers were applied as onlay grafts because no nonunion was associated with a large segmental defect. Cancellous autogenous bone graft from the iliac crest was used as an additional graft at the proximal and distal junctions of the graft with the bone and at the fracture site in all patients. The average duration of follow-up after the vascularized free fibular transfer was fifty-seven months (range, twenty-eight to 112 months). RESULTS: Sixteen of the eighteen fracture sites united, after an average of 9.4 months (range, three to twenty-four months). Thirteen patients had an excellent result, one had a good result, two had a fair result, and one had a failure of treatment. Four patients had an infection, including one who continued to have a nonunion. The other three patients had union after treatment with antibiotics, debridement, and removal of the hardware. Another patient who had a recalcitrant nonunion eventually required an above-the-knee amputation. CONCLUSIONS: On the basis of this review, we suggest that microvascular fibular transfer combined with autografting is an appropriate treatment option for difficult nonunions associated with previously irradiated bone.

Adolescent↗