Biomedical subjects

R S Davidson

Publications and source records attributed to R S Davidson.

At least 19 recordsLinked to original sources

PubMed2002

Displaced fractures of the hip in children. Management by early operation and immobilisation in a hip spica cast.

Fractures of the hip in children have been associated with a very high rate of serious complications including avascular necrosis (up to 47%) and coxa vara (up to 32%). Over a period of 20 years, we have treated displaced fractures by early anatomical reduction, internal fixation and immobilisation in a spica cast to try to reduce these complications. We have reviewed 18 patients who had a displaced non-pathological fracture of the hip when under 16 years of age. Their mean age at the time of the injury was eight years (2 to 13). They returned for examination and radiography at a mean follow-up of eight years (2 to 17). Each patient had been treated by early (" 24 hours) closed or open reduction with internal fixation and 16 had immobilisation in a spica cast. By Delbet's classification, there was one type-I, eight type-II, eight type-III, and one type-IV fractures. There were no complications in 15 patients. Avascular necrosis occurred in one patient (type-III), nonunion in one (type-II, one of the two patients who did not have a cast) and premature physeal closure in one (type-I). There were no cases of infection or complications as a result of the cast. Our treatment of displaced hip fractures in children by early reduction, internal fixation, and immobilisation in a spica cast gave reduced rates of complications compared with that of large published series in the literature.

Adolescent↗

PubMed2001

Angle-closure glaucoma in association with orbital pseudotumor.

PURPOSE: To describe the pathophysiology of angle-closure glaucoma secondary to idiopathic inflammatory orbital pseudotumor. DESIGN: Retrospective, small noncomparative case series. PARTICIPANTS: Three patients with angle-closure glaucoma and orbital pseudotumor. METHODS: The pathophysiology of this entity was investigated using magnetic resonant imaging (MRI) and ultrasound biomicroscopy (UBM). MAIN OUTCOMES MEASURES: Clinical features, anterior chamber angle configuration, and intraocular pressure. RESULTS: Angle closure from anterior rotation of the ciliary body caused by choroidal effusions secondary to pseudotumor was demonstrated using MRI and UBM. Two of the three cases resolved after treatment for orbital pseudotumor. CONCLUSIONS: Idiopathic orbital pseudotumor is a cause of secondary angle-closure glaucoma. The mechanism of angle closure is anterior rotation of the ciliary body secondary to choroidal effusions resulting from the orbital inflammation.

Adult↗

PubMed2001

Metatarsal lengthening.

Metatarsal lengthening for brachymetatarsia is a good procedure that can improve appearance and function. There are risks to these procedures, which should be understood thoroughly.

Bone Lengthening↗

PubMed2001

When does the flat-top talus lesion occur in idiopathic clubfoot: evaluation with magnetic resonance imaging at three months of age.

Flat-top talus has been described as a pathologic change secondary to idiopathic clubfoot condition and/or as a direct result of nonoperative manipulation involving forced dorsiflexion and molding of the cartilaginous talus. No definitive study, however, on the etiology and the timing of the flat-top talus deformity has been performed to date. The authors evaluated the magnetic resonance images of eleven patients with idiopathic clubfoot deformities treated with 2 to 3 months of casting to assess if flattening of the talar dome occurred at this age with this amount of casting. All children were 3 months of age, were casted for a maximum of 2 to 3 months, and sedated before MRI examination. The images were evaluated for maximum talar head height, maximum talar body height, and deviation of the talar body from a perfect circle. Maximum talar head height ranged from 4 to 9 mm, maximum talar body height ranged from 6 to 10 mm. Eight of the eleven had maximum talar body measurements 3 to 5mm greater than maximum talar head height. Three of the eleven patients had head and body size of equal proportion. Two of the eleven had a talar body that was within 1 mm of a perfect circle. The remaining nine patients had perfectly round talar bodies. In the senior author's (RSD) experience with treating clubfeet, a substantial increase has been seen at operation in flat-top tali among children that were casted for more than 1 year before surgical correction, compared to children casted for 3 months before surgical correction. The current investigation indicated that although tali of children with clubfeet are abnormally shaped, the talar body remains larger than the talar head and maintains its roundness after two to three months of corrective casting. Maintenance of cast treatment for more than three months may lead to the flat-top talus deformity. The authors recommend surgical intervention following three months of failed manipulation and casting to prevent this deformity.

Casts, Surgical↗

PubMed2000

Growth disturbances after distal tibial physeal fractures.

Twenty-four patients with distal tibial growth disturbance were reviewed. Disturbances were classified as physeal bar (prior to deformity), angular, linear or combined deformities. Treatment consisted of osteotomy in fourteen, epiphyseodesis in seven, excision of bony bar in two, and observation in one patient. Follow up was an average 36.6 months (range 4-129 months) after treatment of growth disturbance. The age at time of injury was 10.4 years of age average (range 3-15 years). There were 12 SH2, 2 SH3, 7 SH4, and 3 SH5 distal tibial physeal fractures. Thirteen of 15 fractures considered high energy and only 1 of 9 fractures considered low energy resulted in angular deformity. Angular and linear deformities presented an average 46 months (range 12-120 months) and physeal bars at an average 14 months (range 6-25 months) after injury. Patients with a delay in presentation of growth disturbance greater than 24 months had angular deformities in 92% compared with 33% in children presenting less than or at 24 months. Treatment based on type of deformity, age at time of injury, and growth remaining was considered successful in 83%. Patients with angular or linear deformities were more likely to present late, have high energy injuries, be male patients and have Salter-Harris types IV and V. Early diagnosis and treatment of growth disturbance can prevent severe deformity.

Adolescent↗

PubMed2000

Talo-navicular arthrodesis for residual midfoot deformities of a previously corrected clubfoot.

Triangular navicular, dorsal-lateral subluxation of the talo-navicular (TN) joint with a secondary forefoot cavovarus deformity, and degenerative changes of the TN joint are frequent causes of residual clubfoot deformity and pain in the midfoot after surgical correction. This study investigates the usefulness of TN arthrodesis to correct these deformities and to resolve symptoms resulting from these deformities. During the period from 1991-1996, the senior author performed 19 TN fusions (16 patients) for the above residual clubfoot deformities involving a painful TN joint. Eight of the procedures (seven patients) also required a lateral column shortening with a calcaneal wedge osteotomy to allow for a complete correction of the TN joint. The procedure was only performed in cases involving a hindfoot that was adequately aligned during a previous clubfoot correction. The average age of the patients at the time of surgery was 11 years (range: 4-20). One patient (bilateral procedures) was lost to follow-up. Fifteen patients (17 procedures) were followed-up for an average of four years (range: 2-6). All patients reported symptomatic improvement after the TN arthrodesis. Fourteen of the patients (15 procedures) were completely satisfied. The remaining patient (bilateral procedures) was only partially satisfied due to the subsequent development of navicular-cuneiform osteoarthritis in both feet. Two cases (2 patients) developed complications requiring a second procedure for satisfactory results. In addition, the procedure resulted in an improvement of the talus-first metatarsal angle on both antero-posterior and lateral radiographs. TN arthrodesis produced a correction of the residual clubfoot deformities of the midfoot and resulted in satisfactory clinical improvement in all the patients.

Adolescent↗

PubMed1999

Surgical management of calcaneal unicameral bone cysts.

Unicameral bone cysts are not seen commonly in the calcaneus. Little is known about the etiology and natural history of these lesions. Calcaneal cysts often are symptomatic, although some of these lesions are detected as incidental findings. Treatment has been advocated based on the fear of pathologic fracture and collapse. Several published series have been divided in their favor for either open treatment or injection management. These series are small, and the optimal treatment is still in question. The current study compared the efficacy of methylprednisolone acetate injection treatment with curettage and bone grafting in the treatment of unicameral bone cysts of the calcaneus. All patients treated for unicameral bone cysts of the calcaneus during the past 7 years at two institutions were reviewed. Eleven patients met inclusion criteria. All diagnoses were confirmed radiographically or histologically. Demographic information, presenting complaints, diagnostic imaging, treatment modalities, and outcome were analyzed. Long term radiographic and subjective followup was obtained. Eighteen surgical procedures were performed on 11 patients with 12 cysts. Nine injections performed on six patients failed to show healing of the cyst. Nine cysts treated with curettage and bone grafting showed cyst healing. At mean followup of 28 months (range, 12-77 months), all 11 patients had no symptoms; there were no recurrences of the cyst in the nine patients who underwent bone grafting and persistence of the cyst in the two patients who underwent injection therapy. This review reports one of the largest series of cysts in this location. The results indicate that steroid injection treatment, although useful in other locations, may not be the best option for the management of unicameral bone cysts in the calcaneus. Curettage and bone grafting yielded uniformly good results.

Adolescent↗

PubMed1999

Diagnosing aneurysmal and unicameral bone cysts with magnetic resonance imaging.

The differential between aneurysmal bone cysts and unicameral bone cysts usually is clear clinically and radiographically. Occasionally there are cases in which the diagnosis is not clear. Because natural history and treatment are different, the ability to distinguish between these two entities before surgery is important. The authors reviewed, in a blinded fashion, the preoperative magnetic resonance images to investigate criteria that could be used to differentiate between the two lesions. All patients had operative or pathologic confirmation of an aneurysmal bone cyst or unicameral bone cyst. The authors analyzed the preoperative magnetic resonance images of 14 patients with diagnostically difficult bone cysts (eight children with unicameral bone cysts and six children with aneurysmal bone cysts) and correlated these findings with diagnosis after biopsy or cyst aspiration and contrast injection. The presence of a double density fluid level within the lesion strongly indicated that the lesion was an aneurysmal bone cyst, rather than a unicameral bone cyst. Other criteria that suggested the lesion was an aneurysmal bone cyst were the presence of septations within the lesion and signal characteristics of low intensity on T1 images and high intensity on T2 images. The authors identified a way of helping to differentiate between aneurysmal bone cysts and unicameral bone cysts on magnetic resonance images. Double density fluid level, septation, and low signal on T1 images and high signal on T2 images strongly suggest the bone cyst in question is an aneurysmal bone cyst, rather than a unicameral bone cyst. This may be helpful before surgery for the child who has a cystic lesion for which radiographic features do not allow a clear differentiation of unicameral bone cyst from aneurysmal bone cyst.

Adolescent↗

PubMed1998

Neoadjuvant chemoradiotherapy for esophageal cancer: is it worthwhile?

BACKGROUND: With promising results from several institutions, many centers began treating patients with esophageal cancer with neoadjuvant chemoradiotherapy (NC) followed by esophagectomy. This approach is demanding for the patient and has not been proved to be better than esophagectomy alone. OBJECTIVE: To assess survival time and measures of quality of life associated with NC. DESIGN: A retrospective review during 1990 to 1996. SETTING: The 3 tertiary academic hospitals affiliated with the University of Massachusetts Medical School, Worcester. PARTICIPANTS: All patients (N=51) with cancer of the middle or lower esophagus who were treated with NC followed by esophagectomy during this period. MAIN OUTCOME MEASURES: Median and 1-, 2-, and 3-year survival times; median preoperative treatment time (first office visit for surgical consultation before beginning NC to the date of surgery), median hospital stay, and postoperative swallowing function. RESULTS: The median survival time of all patients was 16.3 months; 1-, 2-, and 3-year overall survival rates were 67%, 46%, and 39%, respectively. The median hospital stay was 12 days. The median postoperative treatment time was 3.3 months, which was 20% of the median survival time. Of the 51 patients, 19 were alive with a median follow-up time of 2.5 years. Twenty-nine percent of the patients had a complete pathological response with median and 1-, 2-, and 3-year survival rates of 17.5 months, 73%, 57%, and 57%, respectively. Palliation of dysphagia was excellent, with 44 (93%) of 47 operative survivors taking either a soft diet (18 [38%]) or a regular (26 [55%]) diet by the first postoperative visit. CONCLUSIONS: Median survival time with NC followed by esophagectomy for resectable cancer of the esophagus does not appear to be significantly better than that reported for esophagectomy alone. Further, treatment time with NC consumed 20% of survival time. Examining only these outcome variables suggests that NC is not worth-while. However, examining a longer-term outcome survival variable, such as 3-year survival time, suggests that NC followed by esophagectomy may result in greater long-term survival than that reported for esophagectomy alone. We conclude that further randomized, controlled studies are necessary before NC followed by esophagectomy is considered superior to esophagectomy alone for the treatment of resectable esophageal cancer.

Adenocarcinoma↗

PubMed1997

Accessory soleus muscle. A report of 4 cases and review of literature.

Cadaveric studies have demonstrated the incidence of an accessory soleus muscle ranges from 0.7% to 5.5%. The differential diagnosis of a painful soft tissue mass in the posteromedial region of the ankle includes ganglion, lipoma, hemangioma, synovioma, and sarcomas. In light of these possibilities, most of the early reports of accessory soleus included evaluation and treatment with biopsy, fasciotomy, or excision. Four patients, ranging in age from 14 to 66 years of age at the time of presentation, are discussed. Reports in the literature indicate that accessory soleus is a benign condition, and in most patients, a conservative approach is indicated. In addition, magnetic resonance imaging is the preferred study for the evaluation of this condition. If a diagnosis of accessory soleus is made, and the patient has no symptoms, observation is recommended. However, if the patient has symptoms, fasciotomy generally is a successful form of treatment. For symptoms that persist after fasciotomy, excision of the accessory soleus can be curative.

Adolescent↗

PubMed1997

Pediatric fracture without radiographic abnormality. Description and significance.

With an expanding application of magnetic resonance imaging in acute musculoskeletal injury, an increasing number of occult traumatic lesions of bone are being identified. The authors describe the entity of fracture without radiographic abnormality, which as the name suggests is a bony injury not apparent on plain radiographs. The clinical significance and potential sequelae have not been defined in the pediatric patient. Accordingly, the purpose of this study is to describe and classify the entity of the pediatric fracture without radiographic abnormality and delineate its importance and appropriate management. Twenty-five children were seen primarily or referred to The Children's Hospital of Philadelphia after having sustained an acute traumatic injury; all refused to bear weight or use their extremity, and all had initial plain radiographs that were interpreted as normal. Subsequent magnetic resonance images of all 25 children showed an occult fracture. These included Salter-Harris fracture Types II (two patients), III (one patient), and IV (three patients), intraosseous epiphyseal fractures (18 patients), and a metaphyseal diaphyseal fracture (one patient). Four patients with intraosseous epiphyseal fractures ultimately sloughed a portion of their articular cartilage, as observed at arthroscopy. The decision to proceed with magnetic resonance imaging in the evaluation of a child who refuses to use an extremity depends on many variables. However, magnetic resonance imaging has proven useful in revealing fractures without radiographic abnormality and in ruling out other pathosis.

Adolescent↗

PubMed1996

Slipped capital femoral epiphysis. The prevalence of late contralateral slip.

We evaluated the prevalence of slipped capital femoral epiphysis in the contralateral hip of 169 children who had been managed with pinning in situ and thirty who had been managed with immobilization in a spica cast. Only children who had initially been seen with a unilateral slip and had been followed for a minimum of two years or until skeletal maturity were included in the study. The average duration of follow-up was 3.6 years (range, 0.5 to 9.5 years) for the group that had been managed with a cast and 2.8 years (range, 1.0 to 8.3 years) for the group that had been managed operatively. In sixty-one (36 per cent) of the 169 patients who had had operative treatment and two (7 per cent) of the thirty who had been managed with a spica cast, a slip subsequently developed in the contralateral hip; this difference was significant (p = 0.001). On the basis of these findings, we recommend that closer attention be paid to the potential development of a slip in the contralateral hip after pinning.

Adolescent↗

PubMed1996

Magnetic resonance imaging of skewfoot.

Magnetic resonance imaging was used to visualize the ossified and unossified portions of the bones and soft tissues of the feet in order to evaluate the tarsometatarsal anatomy in sixteen children, three months to six years old (mean, fifteen months old), who were seen in the orthopaedic clinic with a suspected diagnosis of skewfoot. Twenty-seven feet were clinically abnormal and five were normal. Of the abnormal feet, twenty-six had a radiographic diagnosis of skewfoot and one, of simple metatarsus adductus. Of the skewfeet, seven had a talocalcaneal angle of 45 degrees or more as measured on the lateral radiograph and six had a talocalcaneal angle of 45 degrees or more as measured on the anterior radiograph. Valgus deformity of the hindfoot was not apparent on clinical examination in any of the children. The talocalcaneal angles measured on the magnetic resonance images corresponded poorly with those measured on the radiographs, possibly because it is not possible to simulate weight-bearing during magnetic resonance imaging or because the effect of partial volume averaging on thin sections. However, magnetic resonance imaging demonstrated the shapes of the bones and the positions of the unossified portions of the bones. Magnetic resonance imaging showed lateral subluxation of the navicular in twenty-four skewfeet, plantar subluxation in ten, and medial subluxation of the first metatarsal on the medial cuneiform in twenty-five. The alignment of the lateral margin of the calcaneus and cuboid on the magnetic resonance images was normal in all patients. Magnetic resonance imaging has the unique ability to show the cartilaginous and ossified portions of the developing bones of the foot.

Child↗

PubMed1996

Screw fixation of Grade III slipped capital femoral epiphysis.

From 1987 to 1992, 161 children were treated at The Children's Hospital of Philadelphia for slipped capital femoral epiphysis. Of these, 23 patients (23 hips) had Grade III slips (> 50%). Fixation was achieved by 1 or 2 screws in all patients. Twenty-one of 23 patients were available for followup (average followup, 2.8 years). Four slips were acute, 11 were acute-on-chronic, and 6 were chronic. At the most recent followup, radiographs were taken and a Harris Hip Score was assigned for each patient. Stabilization without progression of slip at followup was achieved in all patients. Screw placement was satisfactory per the criteria of Stambough in all patients. Four children (19%) had major complications: Three (1 acute slip and 2 acute-on-chronic slips) had avascular necrosis of the femoral head; One (chronic slip) had chondrolysis. There were no immediate postoperative complications. The mean Harris Hip Score for these 4 patients was 85 points, versus a mean score of 94 points for all 21 patients. Chronic Grade III slipped capital femoral epiphysis can be treated safely and effectively by screw fixation. Five of 6 patients had satisfactory results; the only exception had evidence of chondrolysis preoperatively. Acute and acute-on-chronic Grade III slipped capital femoral epiphyses treated with screw fixation are less predictable. In 15 patients, reduction occurred in 9 hips despite deliberate avoidance of forceful manipulative maneuvers. Avascular necrosis developed in 3 (33%) of these 9 hips. Reduction of the acute component of the slip during screw fixation, whether deliberate or not, indicates gross instability. It is hypothesized that avascular necrosis may be associated with injury to the epiphyseal vasculature occurring at the time of the acute slip.

Adolescent↗

PubMed1996

Valgus slipped capital femoral epiphysis. Fact or fiction?

The cases of 2 patients with valgus slipped capital femoral epiphysis are presented. Additional imaging studies provide support for true posterolateral epiphyseal displacement. Increased femoral anteversion and coxa valga contribute to the pathogenesis of valgus slipped capital femoral epiphysis. In situ pin fixation is recommended for stable valgus slipped capital femoral epiphysis. The importance of valgus slipped capital femoral epiphysis lies in its recognition and appropriate screw placement when internal fixation is used. The percutaneous technique should be used with caution. A limited open technique is recommended when the anterior skin portal is near the femoral neurovascular bundle.

Child↗

PubMed1995

Distraction osteogenesis for congenitally short lesser metatarsals.

Six lesser metatarsal lengthening procedures were performed in three patients using a miniature external fixator to perform distraction osteogenesis. The metatarsals were lengthened an average of 15.5 mm. The external fixator was left in place for an average of 15.5 weeks, with additional time in a cast or cast shoe. Complications included five occurrences of infection, two cases of premature healing of the osteotomy, one nondisplaced fracture through the new bone formation, and hypertrophic granulation at a pin site. While all metarasals were successfully lengthened, two rays (one patient) had symptomatic stiffness at the metatarsophalangeal joint with continued metatarsalgia.

Adolescent↗

PubMed1995

Complications in children managed with immobilization in a halo vest.

Thirty-seven patients who were three to sixteen years old were managed with immobilization in a halo vest between 1987 and 1993. Twenty-four patients (65 per cent) had the halo vest applied in conjunction with operative arthrodesis of the cervical spine; the remaining thirteen patients (35 per cent) had the halo vest applied to immobilize the cervical spine after trauma. Complications occurred in twenty-five patients (68 per cent). Pin-site infections were the most common complications, developing in twenty-two patients. Grade-II infections (purulent drainage) developed more frequently in children who were eleven years old or more: they were identified in five of fourteen such patients, compared with two of twenty-three patients who were ten years old or less. There was a tendency toward more grade-I infections (non-purulent drainage, with or without erythema) and loosening of the pins in the children who were ten years old or less: eleven of twenty-three such patients had each of those complications, compared with four of fourteen children who were eleven years old or more. Both loosening and infection occurred more frequently at the anterior pin sites. Other complications included one dural penetration, one transient injury of the supraorbital nerve, and three pin-site scars that were considered by the family to be objectionable. There were no complications related to the vest part of the halo vest. Younger patients who had a halo construct with more than four pins (multiple-pin constructs) had a similar rate of complications compared with patients who were managed with a standard four-pin halo construct.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Intraoperative anaphylaxis due to exposure to latex (natural rubber) in children.

Intraoperative anaphylaxis secondary to exposure to latex is a serious and potentially life-threatening phenomenon that has been recognized more frequently in recent years. Between 1989 and 1992, twenty-one patients had a Type-I (anaphylactic) reaction to latex intraoperatively at The Children's Hospital of Philadelphia. Twelve (57 per cent) of these patients had spina bifida. Six patients (29 per cent) had cerebral palsy, and five of them had a ventriculoperitoneal shunt. Of the remaining three patients, one (5 per cent) had exstrophy of the bladder, one had VATER syndrome, and one had Duchenne muscular dystrophy. All of the patients had had at least two previous operative procedures. Overall, sixteen patients (76 per cent) had a ventriculoperitoneal shunt. The manifestations of the allergic reaction included a rash in fifteen patients (71 per cent), hypotension in fifteen, tachycardia in eleven (52 per cent), bronchospasm in ten (48 per cent), bradycardia in two (10 per ent), and cardiac arrest in two. The symptoms occurred within minutes after the induction of the anesthesia in all but one patient, in whom hypotension and cardiovascular arrest developed approximately one hour after the beginning of the operation. Two patients had a full cardiopulmonary arrest while under the anesthesia. All twenty-one patients responded to management; there were no deaths. Of the six patients who had cerebral palsy, five had been managed with a ventriculoperitoneal shunt because of hydrocephalus following a previous intraventricular hemorrhage that was related to prematurity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗