Biomedical subjects
Publications and source records attributed to D I Singer.
We present a 13-year-old gymnast with a stress fracture of the scaphoid. Treatment was successful with immobilization for 8 weeks in a long arm spica cast followed by 4 weeks in a short arm splint.
Two different tendon-to-bone reattachment methods were compared to assess tensile strength and histologic repair. After sharp dissection, rabbit Achilles tendons were reattached to the calcaneus by one of two methods: to abraded cortical bone (group 1) or into a cancellous bone tunnel (group 2). After surgery, each rabbit had its long-leg hip spica-cast in plantar flexion for 3 weeks. The rabbits' tendon-bone junctions were harvested 1, 2, 4, 6, and 12 weeks after surgery. Three rabbits were used for each repair method at each point in time: 2 for strength testing and 1 for histologic analysis. After this preliminary study, tensile strength was tested with another 14 rabbits 2 weeks after surgery. At each advancing point in time, in both groups, increasing tendon-bone strength was found. Ultimate tensile strength was equivalent for test rabbits (both methods after 6 weeks) and control rabbits. There was no significant difference between methods at any point in time. Blinded pathologic evaluation reported similar healing with both methods over time. With both methods, healing occurred with Sharpey fibers attached to the superficial cortex, with tendon resorption occurring in the bone tunnel. The simple method of cortical reattachment was shown to be equal to the more complex bone-tunnel reattachment.
Wilms' tumor is a renal tumor that develops in childhood and is one of the most common malignant tumors in children under 5 years old. Bone metastases are extremely rare in Wilms' tumor, with only two reported cases in adults. We report the case of a patient who underwent nephrectomy for Wilms' tumor at the age of 10 years and presented with a bone mass in his left femur 13 years later.
The tensile strengths of various suture techniques were studied in vitro using rabbit Achilles' and flexor digitorum longus tendons. Two new suture methods, a Double and Triple (modified) Kessler, were compared with the Savage, Indiana and modified Kessler techniques. All were core sutures without epitendinous sutures. All suture techniques were found to be significantly different for 2 mm of gap formation. The study found the Savage technique strongest, followed by the Triple Kessler, the Double Kessler, and finally the Indiana. The Double Kessler was almost twice as strong as the modified Kessler. This study also compared two four-stranded techniques (the Indiana and Double Kessler) and found the Double Kessler stronger. The Double Kessler is a simple yet strong suture and may be useful for flexor tendon repairs.
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To assess the efficacy of an adjunctive epineurotomy in carpal tunnel syndrome, 36 wrists in 33 patients were prospectively randomized into epineurotomy and non-epineurotomy treatment groups. The operating surgeons and evaluating therapist were double-blinded. Patients were evaluated preoperatively and at either 6 or 12 months postoperatively, with 15 patients examined at both postoperative time points. Evaluation consisted of five sensory and four motor tests: static and moving two-point discrimination, Semmes-Weinstein monofilament testing, vibratory (30 and 256 cps) sensibility, and dynamometer testing of grip strength and lateral, three-jaw, and tip pinch strengths. Sensory testing showed overall improvement within both groups postoperatively, but there was no difference between the two groups at either 6 or 12 months postoperatively. Motor testing revealed no improvement in the grip strength or lateral, three-jaw, or tip pinch of either group at 12 months when compared to preoperative levels. Twenty-four of 26 epineurotomy patients and all 10 control patients were satisfied with their clinical outcome 30 months after surgery. The addition of an adjunctive epineurotomy, although safe, offered no clinical benefit in the surgical treatment of carpal tunnel syndrome in this series.
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.
This is the first report of combined digital distraction lengthening followed by free vascularized metatarsophalangeal joint transfer. This restored mobility, stability, length, and growth potential in the ring finger of the mutilated hand in a child.
The efficacy of using hydrodistention and vasodilatory drugs to relieve spasm in arteries was investigated. The femoral arteries of 64 rabbits (divided into five groups) were placed in spasm by the topical application of epinephrine (1 mg/ml). In group A (controls) vasospasm was induced without further treatment. In group B vasospasm was induced, and the arteries were hydrodistended with normal saline. In three additional groups vasospasm was induced and either 10% lidocaine hydrochloride (group C), verapamil hydrochloride (group D), or chlorpromazine hydrochloride (group E) was applied. Thirty minutes later the vessels were hydrodistended. All vessels were measured at set intervals, and some specimens were retained for light and electron microscopy. All methods of spasm relief were successful, although to varying degrees. Hydrodistention alone produced the widest dilation for the longest time. Lidocaine was the most successful drug treatment alone. Verapamil followed by hydrodistention was the most successful combination regimen, but did not produce better results than hydrodistention alone. Hydrodistention alone produced significant arterial wall damage, resulting in permanent structural modifications. Prior vasodilatory drug treatment reduced but did not eliminate hydrodistention damage. Although hydrodistention dilates for longer periods than vasodilatory drugs, the arterial wall damage associated with hydrodistention indicates that it should be used only when all other methods of vasodilation have failed.
Five vascularised allografts of the knee joint were performed in dogs immunosuppressed with cyclosporin A and azathioprine. Three survived with normal function for 3 to 4 months after operation. One of the unsuccessful grafts had a failed vascular anastomosis, the other an inadequate blood level of cyclosporin A. All three successful grafts healed well. In two, bone scans, radiographs and biopsies were indistinguishable from successful autografts; in the third the blood supply to the graft failed despite patent anastomoses but the graft healed well with good function. All three grafts were rejected within 2 to 3 weeks of withdrawal of cyclosporin A and azathioprine. In non-immunosuppressed dogs, allografts of the knee, both vascularised and non-vascularised, were rejected within a few days of operation. In two non-vascularised allografts, administration of cyclosporin and azathioprine had no apparent effect on the rate of rejection of the graft.
Forty-five active flexor tendon implants were evaluated after placement in scarred tendon beds of digits II through V. The implant is constructed of silicone rubber with a Dacron core, terminating in a loop proximally and a metal plate distally. Modification of the implant during the period of study has improved its reliability and longevity. The improvement in total active motion (TAM) averaged 72 degrees during implant functioning (stage I) in a group of digits that before operation were classified as 78% Boyes grade 5 (salvage). Complication rate during stage I was 11% (5 out of 45). Of the 27 digits evaluated after implant replacement by tendon autograft (stage II), there was an overall improvement in 62 degrees total active motion with 70% of digits being Boyes grade 5. Many of the complications were believed to be avoidable with experience. This study demonstrates the feasibility of an active tendon implant and the possibility of a permanent prosthesis.
Toe-to-hand vascularized joint transfers in four children were reviewed 6 to 8 years after operation (average, 6.6 years). Two children had vascularized metatarsophalangeal (MTP) joints. Both children have near normal active range of motion. The transferred epiphyses have provided a major contribution to digital growth. The other two children had second toe proximal interphalangeal (PIP) joints transferred to damaged hand joints. Active PIP joint extension has been disappointing, and the overall growth contribution of the transferred epiphysis has been small. We conclude that MTP to metacarpophalangeal vascularized joint transfer can provide painless, functional, stable motion, with near normal growth potential, and the usefulness of toe PIP to hand PIP joint transfer is limited by the inability to achieve good active extension and limited growth potential.
Four patients with five severely traumatized lower legs but preserved feet were treated with fillet flaps from the foot to cover an elective, below knee amputation stump. The posterior tibial neurovascular bundle nourished and innervated this flap. While the posterior tibial artery and vein may be cut and re-anastomosed to prevent kinking and occlusion, the posterior tibial nerve should always be kept in continuity to maintain the quality of sensation to this flap. Four flaps survived and one necrosed secondary to venous insufficiency. Due to its innervation and the unique qualities of heel skin, the flap is very durable and has endweight-bearing capabilities. This has permitted the fitting of an endweight-bearing, total contact, fully extended, below knee prosthesis that appears to offer significant improvement in ease of use and normality of gait pattern over standard patellar tendon-bearing prostheses.
Postural brachial plexus compression neuropathy occurs more frequently than usually realized. The cause is multifactorial with certain predisposing anatomic and congenital factors that are not uncommon. An inciting event is required to cause a clinically significant syndrome. The event can be a specific traumatic episode or cumulative trauma leading to an adoption of a guarding posture, which results in a self-perpetuating cycle and brachial plexus nerve compression. The diagnosis and management may be complicated by concurrent vascular compression, concurrent reflex sympathetic dystrophy, and associated inflammatory musculotendinous conditions. Diagnosis relies on the appreciation of a peculiar symptom complex of pain and paresthesias. The important clinical signs are a supraclavicular Tinel's sign and a positive stress abduction test. Treatment includes exercises, patient education, and behavior modification. However, misdiagnosis can lead to inappropriate treatment, such as unnecessary carpal and cubital tunnel releases. Operative treatment is reserved for those severe cases that are resistant to extended and intense physical therapy. The preferred surgical technique involves an anterior, supraclavicular approach allowing for complete visualization and release of intrinsic and extrinsic nerve compression. Awareness is the key to making the diagnosis, and successful treatment requires a multidisciplinary approach. It is generally accepted that injuries to peripheral nerves result in serious losses of function. Paresthesias and motor weakness cause immediate functional limitation, and place the hand at risk for further injury. The system has little regenerative capacity, and the chance for recovery is poor even under the best circumstances. Therefore the treatment of acute nerve injuries can be difficult and frustrating.(ABSTRACT TRUNCATED AT 250 WORDS)
Twenty-seven femoral shaft fractures in 23 patients with acute spinal cord injuries were reviewed for evaluation of the outcome of operative versus nonoperative treatment. Three groups were identified: 11 nonoperative, eight early operative, and eight delayed operative. Patients treated initially by nonoperative methods developed five impending nonunions (31%), which subsequently were treated by open reduction and internal fixation. One femur in each of the operative groups developed a refracture after early removal of metal fixation devices. In the delayed operative group, four patients (50%) required manipulation under general anesthesia for treatment of poor knee motion. Patients with complete neurologic lesions whose femurs were treated nonoperatively incurred more complications, i.e., decubitus ulcers, than those treated operatively. Operative stabilization of the femur within six weeks of injury rendered the most favorable outcome with the least number of orthopedic or medical complications in patients with both complete and incomplete cord lesions. All of the eight fractures united.