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Biomedical subjects

J G Seiler

Publications and source records attributed to J G Seiler.

At least 55 records · Page 3Linked to original sources
PubMed1994

Cellular survival and proliferation in autogenous flexor tendon grafts.

In order to investigate fibroblast survival and proliferation in autogenous flexor tendon grafts, hindlimb intrasynovial and extrasynovial donor tendons were placed within the synovial sheaths of the medial and lateral forepaw digits of 21 dogs (42 tendons) and treated with controlled early passive motion. Intravital histologic evaluations with confocal microscopy and biochemical determinations of total DNA content and DNA synthesis were carried out at 10 days, 3 weeks, and 6 weeks. Intravital staining of the extrasynovial tendon grafts demonstrated variable degrees of cellular necrosis at the earliest intervals followed by cellular repopulation with fibroblasts and neovascularization from surface vessels. In contrast, intrasynovial tendon grafts were populated predominantly by viable cells at each interval, with occasional patches of cell necrosis and fibroblast ingrowth. Total DNA content and DNA synthesis values in the intrasynovial donor tendons were significantly lower than those seen in the extrasynovial tendon grafts at each interval. Extrasynovial tendons appear to act as scaffolds, undergoing extensive cellular death followed by a rapid repair response. Findings that intrasynovial tendon fibroblasts survive the tendon grafting process suggest that the nutritional supplies and metabolic requirements of intrasynovial and extrasynovial donor tendons differ largely.

Animals↗
PubMed1994

Determination of the compartment pressure threshold of muscle ischemia in a canine model.

A canine model was used to test the hypothesis that critical intracompartmental pressure leading to ischemic muscle necrosis is linked to diastolic blood pressure. Twenty adult dogs were subjected to an infusion of autologous plasma into the anterolateral muscle compartment of the left hindlimb to create an elevation in compartment pressure. There were four experimental groups of five dogs each. In group I, the compartment pressure (CP) was maintained at the animals' diastolic blood pressure (DBP); in group II, at 10 mm Hg less than the DBP; in group III, at 20 mm Hg less than the DBP; and in group IV, at 30 mm Hg. The pressure was measured continuously in the proximal, central, and distal segments of the compartment during an 8-hour period. Immediately postoperatively, and, on the first, fourth, seventh, and fourteenth days one animal from each group was killed. The tibialis cranialis muscle was then removed and analyzed using light and electron microscopy. The critical pressure threshold for ischemic muscle necrosis was found to be 20 mm Hg less than the diastolic blood pressure.

Analysis of Variance↗
PubMed1994

Sympathetic maintained pain (causalgia) associated with a demonstrable peripheral-nerve lesion. Operative treatment.

Nine patients who had sympathetic maintained pain (causalgia) and a total of ten identifiable lesions involving peripheral nerves were managed with a continuous sympathetic block; repair, reconstruction, or lysis of the involved nerve, or a combination of these procedures; and rotation of a muscle flap over the nerve in an attempt to enhance the blood supply in the area and to reduce scarring in the region surrounding the nerve. The lesions were located in the median nerve at the wrist in five of the patients; in both the ulnar nerve at the elbow and the median nerve at the wrist in one; and in the ulnar nerve at the elbow, the radial digital nerve of the index finger, and the posterior tibial nerve near the ankle in one patient each. The average duration of symptoms before treatment was seventeen weeks. All nine patients had clinical findings that were considered diagnostic of sympathetic maintained pain or causalgia. Electrophysiological evidence of dysfunction of one peripheral nerve or more was found in the eight patients who had an electromyogram and a nerve-conduction study. In all nine patients, the causalgic pain diminished within the first seventy-two hours after the operation, and none of the patients had had any recurrence of symptoms at an average of forty-eight months. Although all of the patients had some residual limitation of function, all had improvement after this treatment, and the improvement was maintained.

Adult↗
PubMed1994

Venomous snake bite: current concepts of treatment.

The optimal treatment of venomous snake-bites remains controversial. Because of the variables involved in treatment, an ideal, prospective clinical trial likely will never be done. The purpose of this article is to review the available treatment methods and outline the treatment methods preferred in our institution for crotalidae envenomation.

Animals↗
PubMed1993

In vitro biomechanical analysis of suture methods for flexor tendon repair.

This study was designed to compare five different suture methods that are used clinically for tendon repair. The flexor digitorum profundus tendons from the digits of adult mongrel dogs and adult human cadavers were used as models. The tendons in zone II of the hand, defined as the region from the distal palmar crease to the insertion of the flexor digitorum superficialis tendon at the middle phalanx, were transected and then were repaired by one of the suture methods developed by Kessler, Tsuge, Tajima, Savage, or Lee. The gliding function and tensile properties of the repaired tendons were evaluated biomechanically at time zero. The Tajima and Savage methods produced better gliding function than the other techniques. In the canine specimens that had been repaired by one of these two methods, the rotation of the distal interphalangeal joint was more than 60% of the rotation of the canine control specimens; only the Savage technique produced a rotation 124% that of the human control specimens. After the Tajima repair, the rotation of the proximal interphalangeal joint was 113% that of the canine control specimens and 157% that of the human controls. In the canine specimens that had had the Tajima or Savage repair, excursion of the tendon was greater than 55% that of the controls. The tendons repaired by the Savage method tolerated a significantly higher ultimate load to failure (14 and 25% that of the canine and human control specimens, respectively) than the other methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Intracompartmental pressure measurements in the normal forearm.

In 20 normal subjects, intracompartmental pressure measurements were made at three different sites in the volar forearm: half the distance between the medial epicondyle and ulnar styloid and at points 4 cm proximal and 4 cm distal. The pressure measurements were made using a hand-held digital compartment pressure monitor. The study demonstrated that in the uninjured volar compartment, clinically significant (5 mm Hg) intracompartmental pressure differences exist over distances as little as 4 cm.

Adult↗
PubMed1993

Autogenous flexor-tendon grafts. A biomechanical and morphological study in dogs.

Intrasynovial and extrasynovial donor autogenous flexor-tendon grafts were placed in the synovial sheaths of the medial and lateral digits of the forepaw in twenty dogs (forty tendons). Postoperatively, the dogs were managed with early, controlled, passive mobilization. Histological and ultrastructural evaluations were carried out at ten days, three weeks, and six weeks, and biomechanical analyses were performed at three and six weeks. The intrasynovial and extrasynovial tendon grafts showed different healing processes histologically. The extrasynovial tendon grafts healed with early ingrowth of peripheral adhesions, which appeared to become larger and more dense over time. These grafts exhibited decreased cellularity and early neovascularization at ten days, and there was evidence of progressive revascularization and cellular repopulation at three and six weeks. In contrast, the intrasynovial tendon grafts demonstrated minimum adhesions, and both cellularity and collagen organization were normal at each time-interval. The intrasynovial grafts had significantly more angular rotation at the proximal interphalangeal joint at three and six weeks than did the extrasynovial grafts (p < 0.05).

Animals↗
PubMed1993

Carpal tunnel release. A prospective, randomized assessment of open and endoscopic methods.

To define the role of two-portal endoscopic carpal-tunnel release as a method for the treatment of compression of the median nerve at the wrist, a prospective, randomized, multicenter study was performed on 169 hands in 145 patients. Either open or endoscopic carpal-tunnel release was performed in all of the patients who had clinical signs and symptoms consistent with carpal tunnel syndrome, had not responded to or had refused non-operative management, and had had electrodiagnostic studies consistent with carpal tunnel syndrome. Follow-up evaluations were performed at twenty-one, forty-two, and eighty-four days. At the end of the follow-up period, both the open and endoscopic methods had resulted in high levels of achievement of the primary outcomes (relief of pain and paresthesias). The numbness and paresthesias were relieved in eighty (98 per cent) of eighty-two hands in the open-release group compared with seventy-seven (99 per cent) of seventy-eight hands in the endoscopic-release group. This parameter was not recorded for three hands in the open-release group or six hands in the endoscopic-release group. The satisfaction of the patients with the procedure, graded on a scale of 0 to 100 per cent, averaged 84 per cent in the open-release group compared with 89 per cent in the group that had had endoscopic release. We found no significant differences between the two groups with regard to the secondary quantitative-outcome measurements, including two-point discrimination, postoperative interstitial-pressure data for the carpal canal, Semmes-Weinstein monofilament testing, and motor strength. The open technique resulted in more tenderness of the scar than did the endoscopic method. Thirty-two (39 per cent) of eighty-two hands in the open-release group and fifty (64 per cent) of seventy-eight hands in the endoscopic-release group were not tender at eighty-four days. This parameter was not recorded for three hands in the open-release group and six hands in the endoscopic-release group. The open method also resulted in a longer interval until the patient could return to work (median, twenty-eight days, compared with fourteen days for the open-release and endoscopic-release groups). Four complications occurred in the endoscopic carpal-tunnel release group: one partial transection of the superficial palmar arch, one digital-nerve contusion, one ulnar-nerve neuropraxia, and one wound hematoma.(ABSTRACT TRUNCATED AT 400 WORDS)

Activities of Daily Living↗
PubMed1992

Intrinsic mitogenic potential of canine flexor tendons.

Recent studies have demonstrated an intrinsic neovascular response in intrasynovial healing tendons, introducing the possibility of mitogenic and/or angiogenic capability of intrasynovial tendon. To explore this hypothesis, healing canine flexor tendons were treated with early passive mobilization and the repair sites analysed at three, ten and 17 days. Specimens were mechanically digested and subjected to a standard BALB/c 3T3 mitogenic assay, which measures the capacity of tissue extracts to induce DNA synthesis and cell division in fibroblasts. Results revealed that both control and repaired flexor tendons possessed mitogenic activity, with the greatest activity observed in control specimens. Decreasing activity was noted as the time between repair and analysis increased. These data provide increasing evidence for the flexor tendon's active role in the healing process, and support the concept that mitogenic or growth-promoting factors are associated with flexor tendons and may be released following injury, during the early stages of healing.

3T3 Cells↗
PubMed1992

Silicone rubber distal ulnar replacement arthroplasty.

We retrospectively reviewed 42 patients who underwent resection of the distal ulna with implantation of a silicone rubber ulnar head prosthesis (45 wrists). Two prostheses were used: the original Swanson prosthesis, and a prosthesis of our own design. Follow-up X-rays showed migration or breakage of 63% of the prostheses. No statistically significant correlation existed between the quality of functional outcome and the integrity of the prostheses. There was no significant difference between pre-operative and post-operative range of motion for the entire group or between patients with broken or intact prostheses. Histological confirmation of silicone synovitis was documented in one patient who required implant removal. We suggest that destabilization and breakage of prostheses result from fatigue failure secondary to the torque generated at the distal radio-ulnar joint during repeated pronation and supination. Use of a silicone rubber ulnar head prosthesis following distal ulna resection is not recommended.

Adult↗
PubMed1992

Endoscopic carpal tunnel release: an anatomic study of the two-incision method in human cadavers.

To determine the relationship of neurovascular structures to the sites of portal placement and transverse carpal ligament division during two-portal endoscopic carpal tunnel release, a study of 20 fresh cadaver specimens was carried out. Open dissection of the carpal tunnel after endoscopic surgery showed complete ligamentous release in 18 hands (90%). In 10 specimens, the procedure was performed as described by Chow. There was one partial transection of the superficial palmar arch (5%), and five specimens (50%) had complete divisions of the superficial palmar fascia with considerable pressure placed on the ulnar nerve at the wrist. A modified technique was used in 10 specimens in which the proximal incision was made in a more distal location and a distally based ligamentous flap was created. The superficial palmar arch and the distal edge of the transverse carpal ligament were visualized directly before passage of the trocar. No complications were noted with this method.

Anthropometry↗
PubMed1992

Acute gout after carpal tunnel release.

A carpal tunnel release was performed on three patients with known gout of the lower extremity but not of the upper extremity. Each patient had a postoperative inflammatory reaction in a treated hand, and there was some suspicion of an infection in two patients. However, the inflammatory reaction resolved only when treated with a combination of anti-inflammatory and anti-gout medication.

Acute Disease↗
PubMed1992

Intercalary flexor tendon grafts. A morphological study of intrasynovial and extrasynovial donor tendons.

Intercalary intrasynovial and extrasynovial flexor tendon graft donors were placed within the synovial sheaths of the medial and lateral forepaw digits of 22 dogs and treated with early controlled passive mobilization. Specimens were studied by light and transmission electron microscopy at 10 and 21 days. Early repair in the extrasynovial tendons occurred by an ingrowth of connective tissue from the digital sheath. Adhesions obliterated the gliding surface and occupied the space between the tendon's gliding surface and surrounding tissues. There was no epitenon response noted in the extrasynovial tendon grafts. While there was considerable new collagen fibril formation within the repair site at the ultrastructural level, there was a lack of longitudinal remodeling. In contrast, the intrasynovial tendon grafts showed early healing, with minimal adhesion formation, by a proliferation and migration of cells from the epitenon. These cells showed greater cellular activity and collagen production at 10 and 21 days compared to cells in extrasynovial tendons at the same intervals. The findings of this study suggest that the use of intrasynovial autogenous tendon graft donors, coupled with early controlled motion, stimulates an intrinsic repair process in both the tendon stump and autogeneous tendon graft. These findings differ significantly from the experimental findings in which extrasynovial, paratenon-covered grafts are used.

Animals↗
PubMed1992

Angiogenesis in healing autogenous flexor-tendon grafts.

On the basis of recent evidence that flexor tendon grafts may heal without the ingrowth of vascular adhesions, eighteen autogenous donor tendons of intrasynovial and extrasynovial origin were transferred to the synovial sheaths in the forepaws of nine dogs, and controlled passive mobilization was instituted early in the postoperative period. The angiogenic responses of the tendon grafts were determined with perfusion studies with India ink followed by cleaing of the tissues with the Spalteholz technique at two, four, and six weeks. A consistent pattern of neovascularization was noted in the donor tendons of extrasynovial origin. Vascular adhesions arising from the flexor digitorum superficialis and the tendon sheath enveloped the tendon grafts by two weeks. By six weeks, the vascularity of the tendon grafts of extrasynovial origin appeared completely integrated with that of the surrounding tissues. Examination of cross sections revealed that the segments of tendon had been completely vascularized by obliquely oriented intratendinous vessels. In contrast, the flexor tendon grafts of intrasynovial origin healed without ingrowth of vascular adhesions. Primary intrinsic neovascularization took place from the proximal and, to a lesser extent, distal sites of the sutures. Examination of cross sections revealed vessels extending through the surface layer of the tendon graft, with small vessels penetrating the interior of the tendons at regular intervals.

Animals↗
PubMed1992

Operative management of displaced femoral head fractures: case-matched comparison of anterior versus posterior approaches for Pipkin I and Pipkin II fractures.

Because of the controversy surrounding the selection of the surgical approach for the operative management of femoral head fractures, we retrospectively reviewed the combined experience with femoral head fractures at two major trauma centers. Forty-three femoral head fractures in 41 patients were identified. Twenty-six of the 43 fractures were Pipkin types I and II, and were managed operatively. Of the 26 patients, 12 with > 2 years of follow-up were managed with posterior surgical approaches and 12 with anterior surgical approaches. These patients were assessed with respect to operative time, estimated blood loss and function, and the radiographs for reduction, avascular necrosis, and heterotopic ossification. There was a significant decrease in operative time, estimated blood loss, and improved visualization and fixation with the anterior approach; however, there was a significant increase in functionally significant heterotopic ossification. The functional results in the two groups were identical; 67% good and excellent in each. There were no cases of avascular necrosis of the femoral head associated with an anterior approach. Because of the greater ease of access to the fracture, the anterior approach is recommended when operative reduction of a displaced Pipkin type I or II is indicated, but newer methods of minimizing heterotopic ossification must be developed.

Adult↗
PubMed1991

A prospective evaluation of the AO/ASIF universal femoral nail in the treatment of traumatic and reconstructive problems of the femur.

Beginning in October 1986, we prospectively evaluated the AO/ASIF Universal Femoral Nail in the treatment of traumatic (89 nails) and reconstructive (11 nails) problems of the femur. For treatment of isolated femoral fractures, the mean time of patient positioning and nail insertion was 2.4 hours with a mean blood loss of 389 ml. Seventy-eight per cent of the patients were followed for a minimum of 12 months. There were no infections, one case of nail failure, two cases of screw fracture, and three nonunions. Sixteen nails have been uneventfully removed. The AO/ASIF femoral nail provides results comparable to other intramedullary interlocking devices.

Adolescent↗
PubMed1991

Tuberculous tenosynovitis of the wrist. Two case reports.

Tuberculosis was first described in 1756 by Acrel in a case report. Subsequent reports of musculoskeletal tuberculosis documented the uncommon occurrence of hand and wrist involvement. The two cases presented here demonstrate the difficulty in eradicating the organism even with modern regimens of chemotherapy. Intraoperative Gram's stain and frozen sections were useful to rule out other etiologies. Firm diagnosis must be established by tissue culture. The first case appeared cured after thorough initial debridement and had no recurrence for 36 years. While recurrences are common in patients treated with debridement alone, most appear within one year after the index procedure. The amount of time that elapsed in this case is unusual and serves as a sobering reminder that tuberculosis may recur at a time distant from the initial procedure. The second patient had tuberculosis diagnosed elsewhere and was treated twice with antituberculous chemotherapy. Although the first course of therapy for six months may have been inadequate, the second course with multiple drugs for 18 months would certainly be considered adequate; yet he had a recurrence in his wrist eight months after completing treatment. These two cases illustrate the fastidious nature of the Mycobacterium tuberculosis organism and the need for a combined treatment protocol of meticulous surgical debridement and combined chemotherapy.

Aged↗