Biomedical subjects
Publications and source records attributed to G M Rayan.
Electrodiagnostic studies provide valuable information that can be a useful adjunct to careful clinical evaluation in the diagnosis of compression neuropathy. Such studies can also help to predict the outcome of treatment and differentiate nerve injuries amenable to successful surgical intervention.
Ulnar nerve compression about the elbow is common. If diagnosed and treated early, satisfactory results can be expected. Severe chronic nerve compression may lead to permanent nerve damage. The diagnosis can be made by careful history, physical examination, knowledge of the nerve anatomy, and sometimes electrodiagnosis. Cubital tunnel syndrome must be differentiated from TOS and ulnar tunnel syndrome. Double-crush syndrome should be ruled out. Nonoperative treatment must be attempted first, whereas surgical treatment is indicated in severe and chronic cases. Satisfactory results can be achieved after surgery if nerve damage is absent and careful attention to technical details and gentle handling of the nerve are exercised.
Sixteen bone blocks from two freshly amputated legs were used to study the effect of CO2 laser on cortical bone. They were divided into two groups. In Group I, the blocks were treated with CO2 laser using 1 mm spot (focused mode). In Group II, they were treated with CO2 laser using 3 mm spot (defocused mode). Two other variables were investigated: the power and time of exposure. Three histologic zones were observed: a superficial zone with black particle deposits (carbonization), an intermediate zone with fibrillations and enlarged empty lacunae, and a deep zone with normal appearing bone. The bony changes in the first two zones combined were superficial in all specimens and did not exceed 200 microns. Increased energy, a focused beam, and time of exposure were all associated with increased matrix changes. CO2 laser can be applied to cortical bone in vitro with minimal residual thermal damage.
The role of vasoactive intestinal peptide (V.I.P.) in nerve regeneration was investigated by assessing the changes in immunoreactive V.I.P. levels in rat sciatic nerves following injury and repair. 60 rats were divided into three surgical groups and one control group: In group I (primary repair), sciatic nerves were divided and immediately repaired; in group II (secondary repair), sciatic nerves were divided and repaired two weeks later; in group III (no repair), sciatic nerves were divided and not repaired; and in group IV (controls), sciatic nerves were exposed but not divided. Animals were sacrificed at three days and at weekly intervals. Their sciatic nerves were extracted and assayed for V.I.P. concentrations by a specific radioimmunoassay. The mean V.I.P. concentration varied between 22 and 46 pg./mg. protein in the control nerves and between 60 and 529 pg./mg. protein in all other groups. In the three surgical groups the levels were significantly higher in proximal than in distal stumps. Following nerve injury, there was an increase in V.I.P. concentration in the injured and repaired areas. This increase was greater in injured non-repaired areas and was highest in the first 48 hours, but continued during regeneration. The accumulation of V.I.P. in divided nerves occurred in response to nerve injury.
Human bite injuries are often believed to be more serious than animal bite injuries. One reason for this distinction might be a species difference in the microbial mouth flora. In order to compare this possibility, we cultured the mouths of humans, dogs, and cats. Human oral flora contained the smallest number of bacteria followed by dog and cat oral flora, respectively. Veillonella parvula was cultured from all humans and was also found in dog and cat mouths, but less frequently. V parvula is not usually considered a virulent organism but occasionally may become a pathogen and should not be overlooked especially following human bite injury.
Three patients are described with distal stenosing tenosynovitis involving the flexor digitorum profundus and the A3 pulley. One patient had isolated distal stenosing tenosynovitis and two patients had combined distal and proximal stenosing tenosynovitis of the flexor digitorum superficialis and the A1 pulley. All three patients with four digits involved had improvement of their symptoms after release of the A3 pulley. When involved, the A1 pulley was released at the same time. Patients with proximal stenosing tenosynovitis may have an associated distal stenosing tenosynovitis that if overlooked may cause persistence of symptoms after surgical treatment.
Recurrent anterior dislocation of the ulnar nerve at the cubital tunnel is reported in two patients. This was due to traumatic attenuation of the flexor carpi ulnaris retinaculum. The mechanism of injury in both patients was a fall with the shoulder abducted and the elbow acutely flexed. Both patients had relief of their neurologic symptoms following anterior submuscular transposition of the ulnar nerve.
Abnormal insertion of an abductor pollicis longus slip into an anomalous thenar muscle was observed during reconstruction of the carpometacarpal joint of the thumb in two patients. The anomalous thenar muscle most probably represents duplication of the abductor pollicis brevis.
Digital sucking is common in children. Although orthodontic complications have been reported, hand complications of digital sucking are seldom described. Five patients are reported; two had digital deformities and three had infections. Deformities of the digits were improved with splinting. Infections required surgical drainage followed by postoperative splint protection to prevent digital sucking. Splinting prohibited sucking in four of five patients.
The incidence of nutritional depletion in 40 rheumatoid patients and the factors that influence these patients' nutritional status were investigated. More than half of the patients (52.5%) were found to be nutritionally deficient.
Intratendinous ganglion is a rare lesion of unknown etiology and natural history that originates within the tendon. A patient is described who presented with a painful swelling over the dorsum of the wrist due to an intratendinous ganglion of the extensor pollicis longus tendon. Treatment consisted of excision of the ganglion and its capsule followed by meticulous repair of the tendon.
The incidence of Eikenella corrodens in the human mouth was studied in 229 individuals. Six (2.6%) had positive cultures. The incidence of positive cultures for the saliva group was 0.6% and for the tooth-scraping group it was 8.2%. When 11 isolates were tested against 33 antimicrobials by disc-agar diffusion, 82% were susceptible to penicillin, cephalothin, and cefoperazone. Susceptibility to the remaining second- and third-generation cephalosporins studied was 100%. We suggest that the use of a second- or third-generation cephalosporin only is appropriate empiric therapy for human bite injuries.
Of four patients with rheumatoid arthritis and Dupuytren's contracture, two were not aware of the presence of Dupuytren's contracture. When both diseases coexist, the presence of rheumatoid hand deformities, especially flexion and ulnar deviation of the metacarpophalangeal joints, may mask the flexion deformity caused by Dupuytren's contracture. Careful clinical examination should rule out the presence of a pathologic fascial cord. When reconstructive surgery is indicated for the rheumatoid hand in the presence of advanced Dupuytren's contracture, staged surgery would be appropriate and reconstruction of Dupuytren's contracture should precede other surgery.
The sciatic nerves of 34 rats were used to study the effects of intraneural, extrafascicular hematoma, exclusive of any other trauma. Electrodiagnostic, histologic, and electron microscopic techniques were used. The amount of nerve fiber damage was assessed using computerized planimetry. The effects of hematoma evacuation were also investigated. Changes consistent with partial denervation, such as prolongation of insertion activity and distal latency, and the presence of positive waves and fibrillations, were present in the blood-injected but not in the control groups. Degenerative nerve fiber changes localized to the area of hematoma were present in the blood-injected group and were significantly higher than those in the control group. Although there was a difference in the amount of nerve damage between the blood-injected and the hematoma-evacuated group (less damage), this difference was not statistically significant. These findings suggest that intraneural extrafascicular hematoma produces electrophysiologic and histologic evidence of axonal degeneration affecting nerve fibers in the vicinity of the hematoma. Early evacuation of the intraneural hematoma appears to slightly reduce the deleterious effects of the lesion.
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We studied the functional results of 18 wrist arthrodeses in nine patients with rheumatoid arthritis. Objective evaluation included radiographic assessment, goniometer assessment of the upper extremity (UE), range of motion (ROM), grip and pinch strength, and the Jebsen-Taylor function test. Subjective evaluation consisted of a questionnaire that compared the upper extremity function of various activities of daily living preoperatively and postoperatively. The mean total range of motion for all patients was below normal on the dominant and nondominant sides, as was the average grip and pinch strength. Results of the Jebsen-Taylor test, compared with results of normal persons, were normal 38% of the time and abnormal 62% of the time. Subjective evaluation revealed postoperative improvement of the hand function in seven patients, whereas the function in two patients remained the same. Bilateral wrist arthrodeses does not seem to adversely affect function of the upper extremity in spite of abnormal grip strength and upper extremity range of motion.
Two patients are reported with full-thickness skin necrosis over the dorsum of the distal interphalangeal (DIP) joints after dorsal splint immobilization in hyperextension to treat acute mallet finger. An investigation was carried out to study the relationship of hyperextension to the dorsal circulation of the DIP joint. In 66 digits, the average degree of DIP joint hyperextension at which the skin blanches was 50% of the total passive hyperextension. It is recommended, therefore, when the DIP joint is immobilized to treat acute mallet finger, the degree at which the dorsal skin begins to blanch must be determined, and the amount of hyperextension should not exceed that degree. Excessive localized pressure to the dorsal skin should be avoided by adjusting the angle of the dorsal splint.
The incidence of and nature of fingernail flora was studied in 20 patients. These patients underwent routine preoperative hand scrubbing in a clinical setting, without nail trimming or cleaning. Nineteen (95%) of 20 had a moderate to heavy growth of Staphylococcus epidermidis. These isolates were very susceptible to antibiotics. Thirteen (65%) of 20 patients had fungi (molds and yeast). In spite of adequate preoperative hand scrubbing, the fingernails were heavily contaminated. Such organisms may become pathogens and should not always be considered contaminants. This study also confirmed the importance of preoperative fingernail trimming and cleaning.