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Biomedical subjects

S B Goodman

Publications and source records attributed to S B Goodman.

At least 73 records · Page 4Linked to original sources
PubMed1996

Biomechanical comparison of posterior internal fixation techniques for unstable pelvic fractures.

Early reduction and rigid fixation of unstable vertical shear pelvic fractures has been shown to decrease the incidence of late sequelae and facilitate early mobilization. The results of fixation of the posterior pelvic ring without anterior fixation are unknown. The purpose of this study was to perform a biomechanical comparison of the most frequently used techniques of posterior fixation for unstable pelvic sacroiliac dislocations in conjunction with ipsilateral rami fractures, i.e., an unstable vertical shear injury. The four methods of posterior fixation tested included sacroiliac (SI) screws, anterior SI plates, transiliac bars, and a combination of SI screws and transiliac bars. Six cadaveric pelvises were tested in axial compression and torsion on a biaxial servohydraulic testing machine. Compared to the intact pelvis, single posterior methods of fixation provided approximately 70-85% resistance to axial and torsional loading. By combining SI screws with transiliac bars, approximately 90% of intact pelvic stability was achieved. Our results suggest that rigid posterior fixation of sacroiliac dislocations alone may obviate the need for additional complex anterior surgical procedures to fix rami fractures.

Biomechanical Phenomena↗
PubMed1996

Tourniquet release: systemic and metabolic effects.

The pneumatic tourniquet produces ischemic changes in limbs. The effects of tourniquet release on systemic blood pressure and metabolic parameters were studied in 11 adult patients undergoing total knee replacement under general anesthesia. Mean arterial pressure (MAP) decreased rapidly after the release of the tourniquet, becoming significant at 3 min and remaining significantly depressed up to 15 min post release. Arterial pH, PaO2, PaCO2, lactate acid, and potassium changed significantly after the release, but normalized within 30 min. These results are notably different from a previous study in a similar patient population undergoing knee replacement under epidural anesthesia. Compared to patients under epidural anesthesia, patients receiving general anesthesia with mechanical ventilation are unable to compensate for the metabolic load caused by the tourniquet release, as the latter group are unable to alter their ventilatory rate. In elderly patients with decreased cardio-pulmonary reserve, this may be of clinical importance.

Adult↗
PubMed1996

Early outcome of total hip arthroplasty using the direct lateral vs the posterior surgical approach.

A consecutive series of 49 patients who had a primary total hip arthroplasty (THA) for osteoarthritis is reviewed to determine the difference in clinical outcome between the direct lateral and the posterior surgical approaches to the hip. Group 1 comprised 28 patients off had THA by the same surgeon using a posterolateral approach. Group 2 comprised 21 patients who had THA using the direct lateral approach, modified from Hardinge. The improvement in the limp, abductor strength, Trendelenburg test, and range of motion over time was similar in the two groups. The average Harris hip score at 1 year was 90 for Group 1 (posterior approach) and Group 2 (lateral approach). At 2-year minimum follow up, the Harris hip score was 94 for both groups. Radiographic review showed that the incidence and severity of heterotopic bone was also similar for both groups. The authors conclude that the clinical and radiographic outcome for THA using the posterior and the lateral approaches to the hip yield similar clinical results.

Aged↗
PubMed1996

Does the immune system play a role in loosening and osteolysis of total joint replacements?

Total joint replacement is a highly successful surgical procedure with an excellent outcome over many years. However, because this procedure is now being performed in younger patients, and because the average age of our population continues to increase, greater expectations have been placed on joint implants in the hope that they will last forever. Aseptic loosening and osteolysis of total joint replacements are the main processes limiting long-term implant survival. This paper focuses on the possible role of immunological mechanisms in the processes of loosening and osteolysis of joint replacements, with special emphasis on polymeric materials. This topic is very controversial: In vitro experiments and in vivo studies in animals and humans are reviewed and provide evidence for both sides of the debate. In some patients, immunological processes appear to be activated after a total joint replacement has been implanted. Specific materials or their by-products might function as haptens and elicit a T-lymphocyte-mediated, delayed hypersensitivity reaction. Many factors probably are important, including the genetic makeup and immune competence of the patient, prior exposure to the same or similar materials, degree of exposure (rate of generation of particles and the efficacy of clearance mechanisms), and characteristics of the particles themselves.

Animals↗
PubMed1996

Influence of callus deformation time. Bone chamber study in rabbits.

Short periods of strain have effects on tissue differentiation in a skeletal defect. Little is known about the importance of the duration of such periods. The authors compared 2 short daily periods of strain pulses that differed only by their duration. This was done by using the micromotion chamber, which is a titanium implant with a transverse intraosseous canal. Fibrous tissue forms in the canal and then is replaced by bone through membranous (metaplastic) ossification. The tissue in the canal can be exposed to cyclic deformation. The chamber allows harvest of the tissue within the canal without disturbing the outer parts of the implant or the surrounding bone, thus enabling repeated experiments in the same animal. Chambers were inserted in 6 rabbits and repeatedly harvested at 3-week intervals. Between harvests, the chambers were subjected to either no motion, 20 cycles once daily during 20 seconds (1 Hz), or 20 cycles once daily during 120 seconds (0.17 Hz). Altogether 39 harvested specimens were studied. The 20-second treatment tended to increase the amount of ingrown bone as compared with no motion, whereas the 120-second treatment caused a marked decrease in bone formation and increase in fibrous tissue. Because the acute tissue trauma appears similar with both deformation treatments, it would appear that the increased fibrous tissue formation with the longer deformation time is caused by the parameters of tissue deformation and not by increased tissue damage.

Analysis of Variance↗
PubMed1995

Incidence of symptom recurrence after hysterectomy for endometriosis.

OBJECTIVES: To determine the relative risk of symptom recurrence and/or reoperation after hysterectomy with ovarian preservation for the treatment of endometriosis. DESIGN: Historical prospective study of patients with endometriosis who underwent hysterectomy with or without ovarian preservation. PATIENTS: One hundred thirty-eight women who underwent hysterectomy with the diagnosis of endometriosis. METHODS: A computer search identified 138 women who underwent hysterectomy with the diagnosis of endometriosis at Johns Hopkins Hospital from 1979 to 1991. Follow-up information was obtained from medical records, outpatient charts, and telephone surveys. RESULTS: Twenty-nine women had hysterectomy with some ovarian tissue preserved; 109 had all ovarian tissue removed. Of those with ovarian preservation, 18 of 29 (62%) had recurrent pain and 9 of 29 (31%) required reoperation. Of those who had no ovarian preservation, 11 of 109 (10%) had recurrent symptoms and 4 of 109 (3.7%) required reoperation. Ovarian conservation was associated with a relative risk for pain recurrence of 6.1 (95% confidence interval [CI] 2.5 to 14.6) compared with patients with oophorectomy in a Cox proportional hazards model. The relative risk for reoperation in patients with ovarian conservation was 8.1 (95% CI 2.1 to 31.3). CONCLUSION: Compared with women who had oophorectomy for endometriosis, patients who underwent hysterectomy with ovarian conservation had 6.1 times greater risk of developing recurrent pain and 8.1 times greater risk of reoperation.

Adult↗
PubMed1994

Cessation of strain facilitates bone formation in the micromotion chamber implanted in the rabbit tibia.

Short, daily periods of externally-applied strain have been shown previously to affect the differentiation of mesenchymal tissue. In this study, we examine the effects of discontinuing a strain protocol known to produce primarily fibrous tissue rather than bone in the micromotion chamber (MC). Five MCs were inserted into the proximal tibial metaphysis of mature male New Zealand white rabbits. The MC has a 1 x 1 x 5 mm pore for tissue ingrowth. After osseointegration of the fixed outer cylinder of the chamber, the inner movable core was manipulated for 40 cycles per day delivered at a rate of 1 Hertz ('40'). This provided motion at the interface between the cylinder and the core. The tissue in the pore was harvested after 3 wks. The MCs were then manipulated at 40 cycles per day for 3 wks and then the manipulations were discontinued for 3 additional wks ('40 + 0'); the contents of the chamber were harvested after 6 wks. Finally, the chambers were left without manipulation ('0') and harvested after 3 wks. Histological sections from unmoved chambers ('0') contained extensive trabecular bone, embedded in a fibrovascular stroma. The '40' specimens were composed primarily of longitudinally orientated fibrous tissue. The '40 + 0' specimens were similar histologically to the '0' specimens. The amount of bone ingrowth expressed as a percentage of the area of the section averaged 37 +/- 6 (mean +/- standard error of the mean) for the '0' specimens, 20 +/- 2 for the '40' specimens and 37 +/- 7 for the '40 + 0' specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

A clinical and radiographic study of the "safe area" using the direct lateral approach for total hip arthroplasty.

The purpose of this clinical and radiographic study is to determine whether the surgeon can remain within the 5 cm "safe zone" while using the direct lateral approach during total hip arthroplasty (THA) without endangering the superior gluteal nerve. The direct lateral approach was used in a prospective, consecutive series of 36 primary THAs in 31 patients performed by one surgeon. At the time of closure of the abductor muscle layer, a small metallic clip was placed at the superior extent of the incision into the gluteus medius. After surgery, the patients were mobilized on crutches with protected weight bearing for either a 6-week (hybrid THA) or 12-week (uncemented THA) period. Before surgery, and at 3, 6, and 12 months after surgery, abductor strength and the Trendelenburg sign were measured by the same physical therapist. The vertical distance from the superior pole of the greater trochanter to the base of the clip was measured on all radiographs of the pelvis and corrected for magnification. Before surgery, only 25 of the 36 hips demonstrated abduction strength of 4/5 or greater. Three months after surgery, 34 hips had a grade of 4/5 or greater for abductor strength. The Trendelenburg sign was positive in 24 of 34 hips before surgery, in 5 hips at 3 months, in 1 hip at 6 months, but negative in all hips by 12 months. The clip was located 3.2 +/- 1.3 cm (mean +/- SD) vertically from the superior pole of the greater trochanter. In 34 of 36 hips (95%), the 5 cm safe zone was respected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

The effects of micromotion and particulate materials on tissue differentiation. Bone chamber studies in rabbits.

Motion at the interface between bone and implants for joint replacement may interfere with osseointegration and prosthesis stabilization. Particulate materials may cause foreign body and chronic inflammatory reactions resulting in bone resorption (osteolysis). The micromotion chamber (MC) and the bone harvest chamber (BHC) were implanted in the rabbit tibia, and the effects of micromotion and phagocytosable particulate materials on tissue formation within the chamber were assessed by studying bone ingrowth into a 1-mm pore. Using the MC, one short daily episode of motion (20 cycles/day, 0.5 mm amplitude) for three weeks decreased the amount of bone ingrowth. Using a different pore configuration, the same parameters of motion increased bone ingrowth. Increasing the amplitude of motion (from 0.5 to 0.75 mm), or the number of daily motion periods (from one to two per day) then decreased bone ingrowth. These studies suggest the existence of a window of externally applied strain: a small stimulus may facilitate and a large stimulus may discourage bone formation within the chamber. Cessation of a given set of motion parameters (producing primarily fibrous tissue) for an additional three weeks was accompanied by tissue differentiation into bone. Using the BHC, small, phagocytosable particles of bone cement, high density polyethylene and cobalt chrome alloy, at a concentration of 1.0 x 10(8) particles/mL, caused a foreign body reaction and inhibited the ingrowth of bone. Particles of titanium alloy had no effect on net bone formation. In studies using normal and immunodeficient rats, T lymphocytes were not a prerequisite for macrophages to phagocytose polyethylene particles. In the clinical situation, micromotion and particulate debris may be synergistic in producing prosthetic loosening. If an implant does not undergo osseointegration due to excessive micromotion, the fibrous tissue interface may provide a conduit for the subsequent migration of particles around the implant.

Animals↗
PubMed1994

An in vitro study of femoral intramedullary pressures during hip replacement using modern cement technique.

Five femora (four cadaveric and one plastic) were used to measure the intramedullary pressures simultaneously at two different locations along the proximal femur during the insertion of bone cement and the femoral component using modern cement technique. The pressures were monitored by transducers located at the midpoint of each femoral stem (P1), and just beyond the tip of the femoral stem proximal to a cement plug (P2). Transient increases in intramedullary pressure were noted during the initial compaction of the bone cement using a conventional device. However, during insertion of the femoral component, the pressures at P1 and P2 increased dramatically to peak pressures exceeding 2385 mm Hg at P1 and 3710 mm Hg at P2 respectively. These pressure elevations were not sustained; eight to 10 minutes after prosthesis insertion, the pressures decreased to below baseline levels in all five femora. This probably resulted from contraction of the cement during the curing phase. Transient elevations of intramedullary pressure to levels greater than 100 times capillary pressure are produced during hip replacement using modern cement technique. The highest pressures are generated during insertion of the femoral component rather than during the cement compaction step. These findings suggest that the use of a cement compactor to improve intrusion of the cement into bone is probably unnecessary.

Bone Cements↗
PubMed1993

The effects of bone cement powder on human adherent monocytes/macrophages in vitro.

This study reports the effects of Simplex bone cement powder (BC) on the proliferation and production of bone resorbing factors in vitro by human adherent monocytes/macrophages. Adherent peripheral blood cells were isolated from seven healthy individuals and exposed to a dispersion of BC powder (1 mg/mL), phytohemagglutinin (PHA, 40 micrograms/mL), or medium alone at different periods of cell incubation (days 0-2, 0-7, 5-7, or 10-12). Cell proliferation was quantified by incorporation of 3H-thymidine uptake. Culture supernatants were evaluated for levels of interleukin 1-like activity (IL-1) by murine thymocyte proliferation assay, prostaglandin E2 (PGE2) by radioimmunoassay, lysosomal enzyme activity (N-acetyl-beta-D-glucosaminidase and beta-glucuronidase using fluorometry, and collagen and casein degrading activity using radioactive substrates. Human adherent peripheral blood cells showed a proliferative response to PHA that coincided with cell maturation; BC did not inhibit PHA-induced cell proliferation of either adherent or nonadherent blood cells, indicating the non-toxic nature of these particles at the concentrations tested. BC stimulated increased release of the lysosomal enzyme N-acetyl-beta-D-glucosaminidase; the levels of PGE2, IL-1, collagenase, and caseinase were unchanged.

Adult↗
PubMed1993

Histological reaction to titanium alloy and hydroxyapatite particles in the rabbit tibia.

The interfacial membrane harvested from failed joint replacements contains particulate debris from the materials used for the implant. To define the tissue response to particulate titanium alloy and hydroxyapatite (HA) alone, 16 mature New Zealand white rabbits were divided into 2 groups of 8 rabbits. Using sterile technique, a drill hole was placed anteromedially in the tibia, 1 cm distal to the knee joint bilaterally. The marrow was scooped out and 0.25 mg of either titanium alloy particles or HA particles were inserted in the right tibia. The titanium alloy particles had a diameter averaging 4.0 +/- 4.4 microns (mean +/- standard deviation) and an aspect ratio (the ratio of the maximum length divided by the maximum width) of 1.84. The HA particles had a diameter of 4.4 +/- 3.3 microns and an aspect ratio of 1.76. The left leg was prepared in a similar fashion, but no biomaterial was implanted. The animals were killed after 16 wk. The harvested tibiae were processed with decalcification and the plastic-embedded sections were subjected to histomorphological analysis. Black titanium alloy particles were present within the bone marrow fat between haematopoietic cells, and within scattered macrophages. The surrounding bone appeared to be unaffected. Within the spongiosa, the HA particles were surrounded by small numbers of mononuclear histiocytes or encased within a shell of new appositional bone. Where HA deposits were exposed to the endosteal aspect of bone, there was scalloping of the surface of the HA in a pattern suggestive of resorption or dissolution of the HA particles.(ABSTRACT TRUNCATED AT 250 WORDS)

Alloys↗
PubMed1993

Radiological and histological study of aseptic loosening using a cemented tibial hemiarthroplasty in the rabbit knee.

Fourteen mature New Zealand white female rabbits had a unilateral cemented, stemmed, titanium, condylar-type tibial hemiarthroplasty, using an anteromedial arthrotomy of the right knee. The articular cartilage and minimal bone were resected. There were two prosthetic groups of seven animals each: a well-fixed, non-loose group and a loose group. In the non-loose group, the implant was inserted into the cement bed and axially compressed until the PMMA had cured. In the loose group, the same volume of cement was allowed to cure on the implant ex vivo; the prosthesis was then implanted to ensure that it was loose fitting. Radiographs were performed at zero and 3 months and graded for new lucent lines. Histological analysis was performed using undecalcified coronal sections, surface stained with toluidine blue with the prosthesis in situ, and the cement mantle preserved. Back-scattered electron microscopy was also performed. The mean cumulative grading of new lucent lines was 0.3 +/- 0.1 for the non-loose group and 2.2 +/- 0.4 for the loose group (P < 0.005). Non-loose prostheses were surrounded by a thin fibrous membrane or bone. Loose prostheses were surrounded by a thicker, fibrous tissue layer, containing histiocytes and giant cells which were more prevalent around cement particles, especially near the prosthetic tip. These findings parallel the histology found at cemented prosthetic interfaces in humans. The results of this study suggest that the fibrohistiocytic membrane commonly found around loose cemented implants may be the result of, rather than the cause of, the loosening process.

Animals↗
PubMed1993

Segmental wall motion abnormalities in patients undergoing total hip replacement: correlations with intraoperative events.

We examined the effect of methylmethacrylate cement on venous embolization and cardiac function in 20 patients having total hip arthroplasty under general anesthesia. Segmental wall motion abnormalities and intracardiac targets (presumably emboli) were investigated by making videotaped recordings of the transgastric short axis and longitudinal 4-chamber views of the heart with transesophageal echocardiography at different points during surgery. The incidence of segmental wall motion abnormalities was the most frequent during insertion of cemented femoral prostheses (8 of 14 patients had wall motion abnormalities). This was significantly different from baseline measurements taken at the beginning of surgery (P < 0.05). In addition, there were also significantly more segmental wall motion abnormalities in patients having a cemented femoral component compared to those having an uncemented femoral prosthesis (P < 0.05). The incidence of wall motion abnormalities during acetabular and femoral reaming and during wound closure was not significantly different from baseline. Intracardiac targets (emboli) were seen in all 20 patients during surgery. The largest number of emboli occurred during reaming of the femur and during insertion of the femoral prosthesis. Significantly more emboli were seen with cemented components (P < 0.02). Most emboli were small (< 2 mm) and appeared similar to the microbubbles produced by agitating saline with a small amount of air. Six patients also had larger (> 5 mm) emboli that appeared to be solid material. One patent foramen ovale was detected (5% incidence). There were no adverse cardiac or neurologic events, and heart rate and arterial blood pressure remained within normal limits throughout surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Bone accretion around polymethylmethacrylate and polyethylene implanted in the rabbit tibia.

This study examines the accretion rate of bone surrounding orthopaedic polymeric implants in different physical forms. Forty mature, female, New Zealand white rabbits were used in the study. Bilateral 6mm drill holes were made in the anteromedial tibias, 1cm from the joint line. The right tibia received a polymeric implant and the left tibia functioned as a prepared but nonimplanted control. The animals were allocated as follows: Group 1--bulk, preformed cooled polymethylmethacrylate (PMMA) plug; Group 2--bulk, doughy PMMA implant; Group 3--cement polymer powder; Group 4--bulk ultra-high-molecular-weight polyethylene (UHMWP) plug; Group 5--UHMWP particles averaging 67.29 mum; Group 6--UHMWP particles averaging 15.68 mum. All animals received the same volume of PMMA or UHMWP. The animals were killed after four months by barbiturate overdose. Beginning four weeks prior to sacrifice, the animals were given tetracycline injections at two-weekly intervals for two consecutive days. The upper tibias were harvested bilaterally and the specimens were processed undecalcified. Using a fluorescent microscope, the distance between successive tetracycline bands was assessed. Doughy PMMA tended to suppress bone formation compared to the control side, whereas preformed PMMA plugs and particulate PMMA polymer did not. This may be due to the heat of polymerization or to the presence of residual monomer in the doughy group. Polyethylene tended to facilitate bone accretion whether in bulk or particulate form when compared to the control side or to doughy cement. This effect was less marked when the cement was in particulate form.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Late rupture of the posterior cruciate ligament after total knee replacement.

To our knowledge there have been no reports of late rupture of the posterior cruciate ligament (PCL) as a cause of instability in PCL-retaining total knee prostheses. In our experience of 150 total knee replacements using PCL-retaining prosthesis, three cases (2.0%) of late rupture of the posterior cruciate ligament have occurred, each leading to chronic instability, disabling pain, and revision arthroplasty. In each case rupture of the posterior cruciate ligament was confirmed at the time of revision arthroplasty. The use of a more constrained prosthesis led to a successful outcome in each case.

Aged↗
PubMed1993

Hysterosalpingography contrast media and chromotubation dye inhibit peritoneal lymphocyte and macrophage function in vitro: a potential mechanism for fertility enhancement.

OBJECTIVE: To determine the effects of hysterosalpingography (HSG) contrast media (CM) and chromotubation dye on peritoneal lymphocyte proliferation and macrophage phagocytosis in vitro. DESIGN: Peritoneal fluid (PF) lymphocytes and macrophages were isolated from 40 subfertile women undergoing diagnostic laparoscopy and 12 fertile women having laparoscopic tubal ligation. Dilutions of renografin, ethiodol, methylene blue, and indigo carmine were added to peritoneal lymphocyte and macrophage cultures. Tissue culture media alone served as control. Lymphocyte proliferation was assessed by hemocytometer counts and 3H-thymidine incorporation. Macrophage function was determined by phagocytosis of fluorescent microspheres. RESULTS: Peritoneal lymphocyte proliferation and macrophage phagocytosis were significantly inhibited by renografin, ethiodol, methylene blue, and indigo carmine in a dose-dependent manner. CONCLUSION: Inhibition of PF immune cell function by HSG CM and chromotubation dye may provide a potential mechanism for fertility enhancement after these diagnostic procedures.

Cell Survival↗