Biomedical subjects
Publications and source records attributed to G K Frykman.
This study provides comparative data relative to the mechanical rigidity, cost, weight, and other features of 13 external fixators for the distal radius. It is our intent that these data be used by the practicing surgeon in the selection of a device that is appropriate to his or her practice and any given patient.
This article presents a continuation of a study of the treatment of scaphoid nonunion with pulsed electromagnetic fields (PEMF) and cast immobilization. Fifty-four patients were reviewed. The overall success rate for healing has decreased since the previous review from 80% to 69%. Proximal pole fractures healed in 50%. Success in nonunions with associated radiographic evidence of avascular necrosis decreased from 89% to 73%. Although we believe that the indications for use of PEMF have not changed significantly, this study suggests that a successful outcome with PEMF and casting is less likely than previously reported. We believe that until additional clinical studies have further defined the indications, treatment protocol, and efficacy of this method PEMF treatment should be a secondary alternative to bone-grafting procedures.
It is well known that tendon or muscle interposition can cause fractures to be irreducible by closed means. A rare tendon interposition of extensor carpi ulnaris occurred in an 11-year-old boy. The isolated displaced distal ulnar physeal injury was the result of a motor vehicle accident. Attempts to perform a closed reduction failed. At operation, an interposed extensor carpi ulnaris tendon was found. After repositioning the tendon, a near anatomic reduction was easily accomplished. Only two cases seem to have been reported in the literature on the need for open reduction of distal ulnar physeal injury, none with an interposed tendon. Interposed extensor carpi ulnaris tendon should be considered as a cause of irreducible displaced distal ulna epiphyseal fracture.
We compared 11 external fixators for treatment of wrist fractures on the basis of rigidity, weight, cost, design characteristics, and provision for allowing wrist motion, and found important differences between them such as rigidity varying as much as 11 times. The Roger Anderson, Hanson Baylor Mini Hoffman, Rectangular Mini Hoffman, and Ace Colles external fixators are lightweight and have low rigidity. The C-series Hoffman unilateral frame and the A.O. have intermediate rigidity. The newly developed methylmethacrylate fixator, the regular Hoffman, the C-series Hoffman bilateral frame, and the Clyburn are more rigid. Although both the Clyburn and the Orthofix allow wrist flexion and extension, the Clyburn is lightweight and the Orthofix has the highest rigidity. These factors are analyzed and reported in a format that will guide the surgeon in the selection of an appropriate fixator for his patient with an unstable wrist fracture.
Vascularized tendon grafts were compared with nonvascularized tendon grafts in a primate experimental model. In four monkeys, seven vascularized extensor hallucis longus grafts were placed in the foot's digital fibroosseous canal and these were compared with eight nonvascularized tendon grafts similarly placed in the opposite extremities. The juncture techniques and postoperative protocols were identical for both tendon groups. All tendons were explored 5 months after insertion. The vascular pedicle was patent in all vascularized tendons. Three tendon ruptures occurred in nonvascularized tendons and only one rupture occurred in a vascularized tendon. The digits with vascularized tendons demonstrated a significantly better simulated total active motion (117 degrees versus 128 degrees, p less than 0.05) than digits with nonvascularized tendons. The difference was even more significant when a localized tenolysis of the proximal juncture of the tendon graft was performed (215 degrees versus 138 degrees, p less than 0.01). This study supports the concept that vascularized tendon grafts may be advantageous in scarred tendon beds.
Sixteen patients with ring avulsion injuries treated at Loma Linda University over 10 years were reviewed. According to Urbaniak's classification scheme, there were two class I, seven class II, and seven class III injuries. Follow-up functional measurements showed that the grip strength of our class II patients were, on the average, no better than that of the class III patients, even though all of class III patients had amputation revisions. Five class II patients required only venous microvascular repair. We propose to modify Urbaniak's classification to IIC to include only ring avulsion injuries with venous compromise. These patients had excellent functional results, with an average total active motion of 224 degrees.
A model was developed in the dog to allow both the metaphysis and epiphysis of the distal ulnar growth plate to be microsurgically revascularised from the pedicle of the anterior interosseous vessels. With both circulations revascularised, grafts retained their structural integrity and growth continued at rates only slightly less than normal (mean 85%). If either or both circulations were not revascularised, growth rates were lower and were associated with skeletal collapse in the ischaemic bone segment.
We have reviewed the morphologic, electrophysiologic, biochemical, and functional methods of evaluating PN regeneration in animal models. There are a large number of anatomic techniques that can provide clear insights into the processes of peripheral nerve regeneration. Since many of these are costly in terms of labor, careful selection of the technique appropriate for the question asked is important. Two of the more important questions are: 1) What are the neurotrophic factors produced by the distal segment that attract the growing axon tip? and 2) What are the components of the basal lamina that facilitate the directed growth of the axons? To answer these questions, whole mount preparations provide the means to economically evaluate the result of experimental manipulation of the environment. Automated nerve fiber counts will be increasingly used to help interpret electrophysiologic studies. Quantitative as well as descriptive ultrastructural analyses will continue to provide valuable data that will be needed in the interpretation of biochemical and histochemical studies. Immunohistochemical probes are sure to become more important as the range of their specificities broadens. With the diversity of anatomic methods available and their capacity to help us visualize the processes occurring during nerve regeneration they will remain a key tool in these studies. Electrophysiologic methods that integrate the CAP and correlate it with the number of functioning NF are most useful. Functional methods are beginning to become more objective and quantitative. The most precise measurements are muscle weight and the isometric response of muscle to tetanic contraction. Sensory function has now been measured objectively by Horch. Single methods of measuring PN regeneration give only limited data, but by combining methods a better understanding of PN regeneration is possible. While understanding the limitations of each method and technique, multi-parameter animal models may provide data most helpful clinically. However, because of great species variability in the reparative response, caution must be given not to extrapolate too much from animal studies. We urge investigators to use the most objective methods available to measure nerve regeneration. Recognizing these limitations, however, animal studies will continue to provide significant insights into PN regeneration and should point the way to improved clinical practice.
We have reviewed the technique of interfascicular nerve grafting and reviewed the results of 60 nerve grafts in 33 patients. After reviewing our results and comparing them with the literature on nerve grafts and direct repairs, the results are comparable and, in some series, better with nerve grafts. These observations support Millesi's original reports of favorable results from interfascicular nerve grafting. Although Millesi's results are better than reports by others, the overall results indicate nerve grafting is a preferable option to repair under tension. The minor sensory loss from the sural nerve donor defect was not bothersome in our patients. We will continue to prefer nerve grafting to extensive mobilization or more than moderate joint flexion to overcome gaps in nerves. Although the critical gap distance remains controversial, the following advantages of nerve grafts remain: increasing comfort in use of the microscope, the ability to do better technical apposition of the nerve fascicle groups, the ability to locate the nerve away from scarred bed, and the ease of repair of the nerve with the joint in a neutral position. These advantages far outweigh the disadvantage of increased operating time and the small sensory loss from the donor nerve harvest. We believe interfascicular nerve grafting is the contemporary standard for closing significant gaps in peripheral nerves.
Seven patients with ruptured flexor tenorrhaphies in zone II had surgical repair of the rupture and completed a second rehabilitation program of active flexion and extension exercises identical to that prescribed after the primary repair. The period between the primary repair and the rupture ranged from 14 to 72 days, with an average of 38 days. The period between the rupture and the secondary repair ranged between 1 and 14 days, with an average of 6 days. Four patients (57%) achieved good to excellent active motion at follow-up. These results are comparable to those obtained by patients with uncomplicated primary repairs that were treated early with passive motion exercises. We conclude that prompt repair of ruptured flexor tenorrhaphies and rehabilitation with active motion exercises is effective and that it should be considered before one chooses flexor tendon grafting.
Microvascular surgery has allowed creative primary reconstruction using undamaged parts of amputated limbs as donor sites. We present a case of lower extremity below-knee amputation salvage with a free flap of heel, calcaneus, and soft tissues from the amputated lower leg, ankle, and foot supplied by the posterior tibial neurovascular bundle.
Twenty toe-to-hand transfers in 17 patients with an average follow-up of 54 months have been reviewed to quantify hand function and donor morbidity. Eleven toe-to-thumb and nine toe-to-finger procedures were performed. Surgical and follow-up data were available for all patients. Twelve patients (14 procedures) were reviewed in detail, with particular attention given to foot and hand function. Total active motion after toe-to-thumb transfer was 48 degrees and 106 degrees after toe-to-finger transfer. Two-point discrimination was less than or equal to 15 mm in 13 digits (65%). Grip and pinch power were related to the number of digits present on the reconstructed hand and to the presence or absence of functioning thenar muscles. Eleven of 12 patients can walk and run normally (mean of 5 years after surgery). Six (50%) cannot wear thongs or heavy boots, but all can wear normal shoes. The transferred great toe decreased in volume by an average of 10% over the years since the operation. Transferred toes became useful digits in the hand, and foot morbidity was minor and not progressive.
Thirty-five of 44 nonunited scaphoid fractures that were at least 6 months old healed in a mean time of 4.3 months during pulsed electromagnetic field (PEMF) treatment using external coils and a thumb spica cast. The mean time from the onset of the fracture to treatment was 40 months. No concurrent operation was performed. Follow-up time averaged 8.4 months. Eight of nine fractures with avascular necrosis healed. Five of eight fractures in the proximal third healed. Twelve (75%) of 16 patients treated in short-arm thumb spica casts and PEMF healed versus 22 (92%) of 24 patients treated initially in long-arm thumb spica casts and PEMF. We have found PEMF to be a reliable alternative method of treating nonunited scaphoid fractures. Because of the low risk, simplicity of use, and reliability, we recommend its consideration in the treatment of undisplaced, nonunited fractures without carpal instability less than 5 years after the injury. Treatment should initially begin with a long-arm cast.
To determine the end point of histopathologic damage in avulsed arteries, the forearm arteries of five monkeys being sacrificed were avulsed longitudinally and samples of proximal and distal arteries prepared for light microscopy and transmission and scanning electron microscopy. A severe and consistent circumferential skip lesion was found on the luminal surface involving the intima and media. In 30 percent of vessels, histopathologic damage extended more than 3.0 cm from the rupture point. Similar circumferential tears occurred on the luminal surface of resected human avulsed arteries collected at the time of replantation surgery. No consistent lesions were noted in resected veins from human avulsed amputations. It is possible that in the human artery (as in the monkey) circumferential lesions frequently extend many centimeters from the rupture point and therefore beyond resection distances. Lesions present in the vessel after resection and microsurgical repair might be the site of thrombosis and subsequent occlusion.
Large wounds of the lower extremity, particularly distal to the knee, have been difficult to cover by traditional means such as skin grafts, local flaps, cross-leg flaps and jump flaps. These wounds, particularly when associated with fractures and osteomyelitis, have frequently resulted in amputation of the lower extremity. Microvascular surgical techniques have allowed the transfer of large flaps of skin and/or muscle from a remote site of the body to the defect in the leg for soft tissue coverage and additional blood supply to the defect. Although these techniques are more tedious and require longer operating times, they usually shorten the patient's hospital stay, heal the wounds faster and shorten disability time. With wider experience, improved techniques and greater microsurgical skill, lower limbs with large defects due to trauma or tumor resection can be salvaged and reconstructed with acceptable risks and minimal donor site morbidity.
The rigidity of four external fixators for the wrist was determined by using the Instron universal testing instrument. Using the equivalent stiffness index, the small A.O. was 7.6, the mini Hoffman was 3.7, Roger Anderson was 3.5, and Ace Colles' was 4.3. Thus, the small A.O. was about twice as rigid overall as the other three external fixators. Twenty-two patients with unstable distal radius fractures were treated with the mini Hoffman external fixator over a 3-year period; and follow-up data were obtained. The average final angle of the distal radial articular surface on the anteroposterior x-ray film was 17.5 degrees. The final angle of the distal radial articular surface on the lateral x-ray film was 2 degrees dorsal. The final height of the distal radial styloid averaged 8 mm. The final range of motion of the wrist compared with the opposite normal hand was extension 77%, flexion 77%, ulnar deviation 82%, radial deviation 73%, pronation 84%, supination 78%, and grip strength 72%. Complications included three cases of broken pins, one of a pin loosening with migration, one case of tendon rupture, and one of intrinsic contracture. From our experience, the Hoffman external fixator gave adequate clinical and functional results and can be used safely in the small to average size patient. A more rigid external fixator should be used for larger and more active patients. External fixation is an excellent way to treat unstable distal radial fractures.
Sixteen patients who underwent partial excision of the triangular fibrocartilage (TFC) to treat chronic wrist pain were studied retrospectively. Eleven patients (69%) had no symptoms at follow-up: Five other patients later underwent distal ulnar resection. All patients over 40 years of age did poorly after the operation. The patients who had no symptoms showed no significant alteration in wrist function after partial excision of the TFC. Removal of a perforated TFC is contraindicated in the presence of radiocarpal or distal radioulnar arthritis.
We studied the cases of eight patients, one with bilateral involvement, who had a rotator cuff tear and an associated lesion delineated roentgenographically - a separate fragment of the acromion that we believe to be an ununited ossification center of the acromion (os acromiale). In reviewing the literature, we found no mention of an association between a rotator cuff tear and os acromiale. It is highly unlikely that such an association is coincidental because it appears that in our patients abnormal motion existed through the site of fibrous union of the acromion and may have contributed to the impingement of the acromion on the rotator cuff. Repair of the rotator cuff with removal of the loose fragment of acromion was done in the six patients who had operative treatment.