Biomedical subjects

L A Feiwell

Publications and source records attributed to L A Feiwell.

4 recordsLinked to original sources

PubMed1995

The effect of chevron osteotomy with lateral capsular release on the blood supply to the first metatarsal head.

The chevron osteotomy is one of the most widely used distal metatarsal osteotomies for the treatment of hallux valgus in adults. Because the osteotomy interrupts the intraosseous blood supply to the metatarsal head, there has always been a concern that the operation could produce osteonecrosis of the metatarsal head, particularly if the important extraosseous blood supply was also damaged. We used latex injection and a modified Spalteholz technique in cadaveric specimens to demonstrate the effect of the chevron osteotomy, with and without lateral capsular release, on the vascular supply to the first metatarsal head. We found an extensive network of extraosseous vasculature to the metatarsal head both proximal and distal to the site of the osteotomy. Both of these vascular networks were preserved when the osteotomy was done properly. Also, an extensive plantar and plantar lateral network of vessels provided circulation to the head. Potential technical flaws in the performance of the osteotomy included cutting of the first dorsal metatarsal artery by overpenetration of the saw blade and incorrect placement of the proximal arms of the osteotomy inside the joint capsule. These technical errors, alone or in conjunction with extensive capsular stripping, can result in damage to the vessels that supply the metatarsal head.

Aged↗

PubMed1994

Anatomic study of arthroscopic debridement of the ankle.

To this date, there have been no published studies correlating gross intra-articular anatomy and the compartments of the ankle that can be instrumented under arthroscopic visualization. The purpose of this study was to demonstrate which areas of intra-articular surface were accessible to the standard portals using a technique that allows direct anatomic correlation. Six fresh cadaver specimens and 12 fresh-frozen, below-knee amputations were used in this study. The 18 ankles were divided into six groups using only one arthroscopic portal site and one instrumentation site per group. Arthroscopic curettes were used to debride only the visualized talar, tibial, and fibular articular cartilage surfaces. After debridement, excision of the distal tibiofibular joint and the talus was performed. The total area of articular cartilage removed with each combination of arthroscope and instrument portal sites was noted, photographed, and recorded graphically. Use of the various combinations of the anteromedial, anterolateral, and posterolateral portals allowed complete access to all surfaces of the tibial plafond, anterior and posterior rims, and the talar dome. Areas that were not accessible by any portal combination were the distal half of the anterior colliculus of medial malleolus, the majority of the lateral talar articular surface, and the inferior half of the lateral malleolar articular surface.

Ankle Joint↗

PubMed1992

A method for measuring foot pressures using a high resolution, computerized insole sensor: the effect of heel wedges on plantar pressure distribution and center of force.

A new, high resolution, pressure-sensitive insole was tested and found to provide reproducible measurements of static and dynamic plantar pressures inside the shoe of normal test subjects under certain conditions. However, calibration between separate sensors was poor and the sensor pads showed significant wear with use. This system was also used to investigate the effect of heel wedges on plantar foot pressure to determine whether this system was sensitive enough to detect the effect of a gross shoe modification on plantar foot pressure. Medial heel wedges decreased plantar pressures under the first and second metatarsals as well as under the first toe, and shifted the center of force laterally in all portions of the foot. Lateral heel wedges decreased pressures under the third, fourth, and fifth metatarsals, increased pressures under the first and second metatarsals, and shifted the center of force medially in all portions of the foot. Our evaluations indicate that it is possible to measure static and dynamic plantar foot pressures within shoes and to study the possible effect of shoe modifications on plantar pressures in controlled gait trials.

Adult↗

PubMedDate not supplied

Anatomic study of arthroscopic portal sites of the ankle.

Numerous anatomic structures are at risk when performing ankle arthroscopy through the more commonly utilized portals. The purpose of this paper was to demonstrate the relative safety of each of the arthroscopic portal and Acufex external ankle distractor pin sites by measuring their proximity to the neurovascular structures surrounding the ankle joint. Six fresh cadaver specimens and 12 fresh-frozen, below-knee amputations were utilized for this study. An Acufex ankle distractor was applied using the standard technique. Anteromedial, anterolateral, anterocentral, posterolateral, and posteromedial portals were placed using an 11-blade scalpel to make 5-mm longitudinal incisions. The joint capsule was penetrated and a 3-mm arthroscope was placed into the ankle joint. The skin surrounding each of the portals was carefully removed and the proximity of any nerves or vessels was measured with respect to the arthroscope. At least one incidence of contact or penetration of a nerve or vessel was noted for each site. The anterocentral portal was at greatest risk for nerve or vessel damage. The anterolateral, anteromedial, and posterolateral portals were the safest areas for portal placement, with no penetration of neurovascular structures in any case.

Ankle↗