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Biomedical subjects

A H Schmidt

Publications and source records attributed to A H Schmidt.

8 recordsLinked to original sources
PubMed1996

Periprosthetic metastatic carcinoma. Pitfalls in the management of two cases initially diagnosed as osteolysis.

Periprosthetic osteolysis is a well-described phenomenon associated with total hip arthroplasty. Two cases are presented in which apparently healthy patients developed lytic lesions adjacent to cementless hip implants. Despite atypical features, the lesions were initially attributed to wear debris-induced osteolysis, and it was discovered during revision surgery that metastatic tumor was present. For one patient, if the initial diagnosis had been correct, subsequent surgery and related complications may have been avoided. It is important to consider the entire differential of radiolucent bone lesions whenever a patient presents with periprosthetic osteolysis. If revision surgery is not warranted on the basis of loosening, then a thorough medical examination, close follow-up evaluation, and/or biopsy should be performed to rule out metastatic disease.

Adenocarcinoma↗
PubMed1995

Nonreamed interlocked intramedullary tibial nailing. One community's experience.

Forty-nine acute displaced tibial fractures (31 closed, 18 open: 5 Grade I, 7 Grade II, 4 Grade IIIA, and 2 Grade IIIB) were treated in 1 community with a standard operative protocol using a distractor without a fracture table, and an unreamed interlocked tibial nail. Forty-six fractures healed (94%). Complications included 3 nonunions (6%), 2 deep infections (4%), 9 delayed unions (18%), 4 angular malunions (8%), 2 rotatory malunions (4%), and 12 interlocking screws bent or broke (24%). Twenty-eight patients (57%) required at least 1 additional operation to obtain union, most commonly dynamization of a statically locked nail. The authors conclude that unreamed tibial nails provide adequate stabilization of displaced tibial fractures and can be used in the management of most open or closed tibial fractures. However, static locking is required in axially unstable fractures. Early dynamization or exchange nailing and bone grafting should be considered to hasten union and avoid screw failure. The distractor is an excellent adjunctive technique for reduction and alignment of tibial shaft fractures during intramedullary nailing.

Adolescent↗
PubMed1995

Fractures of the proximal part of the femur.

The orthopaedic surgeon has a multitude of internal fixation devices and techniques available for use in the treatment of subtrochanteric fractures of the proximal femur. The successful use of second-generation locking nails is technically demanding. Close attention to positioning of the patient, reduction of the fracture, placement of the guide-wire, and insertion of the nail and of the proximal and distal locking screws is mandatory. The newer, high-strength hip-screws allow good fixation of a fracture that extends into the piriformis fossa. If medial comminution is present, this technique is best performed in conjunction with indirect reduction and bone-grafting. With proper technique, these devices allow the surgeon to manage predictably a complex subtrochanteric fracture that previously had to be treated with traction or extensive dissection and with (frequently inadequate) internal fixation.

Adult↗
PubMed1992

Assessment of bone viability in patients with osteomyelitis: preliminary clinical experience with laser Doppler flowmetry.

The intraoperative determination of bone viability is of fundamental importance in the surgical management of osteomyelitis. Recurrent infection will result from inadequate debridement, whereas reconstructive problems will be magnified by overzealous resections. The purpose of this article is to report the use of laser Doppler flowmetry (LDF) as a surgical adjunct allowing quantitative determination of bone viability in patients with osteomyelitis. Twenty-five patients with osteomyelitis underwent surgical debridement using LDF to assist with the intraoperative identification of necrotic bone and have been observed for at least 6 months. The LDF probe is placed directly on the bone and the output signal is channeled into an oscilloscope that calculates and displays the mean value of the signal in millivolts (mV). All patients underwent radical surgical debridement, including hardware removal if present and resection of nonviable bone. Bone debridement was continued when possible until LDF measurements in excess of 100 mV were obtained. Information regarding bone vascularity obtained with the LDF had a direct influence on the extent of bone debridement in all cases. The patients have been observed for an average of 16 months. No complications were associated with the use of LDF. All readings were pulsatile. Five patients had recurrence of infection. The average LDF reading following debridement for patients with recurrent infection was 72 mV, compared to 107 mV for patients without recurrence (p less than or equal to 0.025). All fractures were healed, although some required supplemental surgical management, including bone grafting or external fixation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Muscle injury induced beneath and distal to a pneumatic tourniquet: a quantitative animal study of effects of tourniquet pressure and duration.

Previous recommendations regarding the "safe" period of tourniquet hemostasis were based largely on studies of ischemia distal to the tourniquet. This study quantitatively analyzed skeletal muscle injury induced beneath and distal to a pneumatic tourniquet applied to the hindlimbs of rabbits for 1, 2, or 4 hours with a cuff inflation pressure of 125, 200, or 350 mm Hg. Technetium Tc 99m pyrophosphate incorporation after systemic injection (Tc 99 uptake) and correlative histology were used to evaluate tissue damage 2 days after tourniquet application. Compared with the contralateral control limbs, compression and ischemia induced statistically significant increases in Tc 99 uptake in the thigh and leg regions of all groups. Pyrophosphate incorporation was significantly greater in the thigh region than in the leg region after 2 hours of compression in the 200 and 350 mm Hg pressure groups and following 4 hours of compression in all pressure groups. Focal and regional fiber necrosis and degeneration were observed in thigh muscles after 2 hours of tourniquet compression. Two hours of continuous tourniquet application at clinically relevant cuff inflation pressures induced significant skeletal muscle necrosis beneath the tourniquet. Use of the lowest possible inflation pressure for a limited duration should minimize the degree of tissue injury caused by tourniquet application.

Animals↗
PubMedDate not supplied

Pelvic osteotomy for bladder exstrophy.

Twenty-five patients with bladder exstrophy underwent pelvic osteotomy at or before initial bladder closure and anterior abdominal repair. Ten patients underwent bilateral iliac osteotomies before 1977. An alternative procedure consisting of bilateral superior pubic ramotomies has been used in 15 patients since 1977. In all patients, successful tension-free closure of the abdomen was achieved. Long-term follow-up of these two groups of patients shows no difference in the degree of pubic diastasis, which was asymptomatic. Posterior iliac osteotomy requires two additional incisions, longer operative time, and postoperative immobilization. We therefore recommend bilateral superior pubic ramotomy as an alternative procedure in initial reconstruction of the anterior abdomen in patients with bladder exstrophy.

Adolescent↗