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Biomedical subjects

P W Allen

Publications and source records attributed to P W Allen.

At least 19 recordsLinked to original sources
PubMed2005

Ilizarov external fixator: acute shortening and lengthening versus bone transport in the management of tibial non-unions.

Eighteen patients with tibial shaft non-unions were treated by the Ilizarov method between March 1995 and September 2001 by the senior author. Three subgroups of six patients each were treated by either acute shortening and lengthening, bone transport or simple stabilisation with a frame. All aspects of non-union, infection, shortening, deformity and bone loss were addressed by using Ilizarov principles. There were 10 cases of infected non-unions in the entire series. Bone resection in the shortening group was between 3 and 6 cm (median 4.6) compared to 3-7.5 cm (median 5.9) in the bone transport group. Union was achieved in all the patients with the average time to union at 12.1 months, 17.2 months and 8.0 months, respectively. The bone transport group required additional bone grafting in five patients (83.3%) prior to union compared to one (16.7%) in the acute shortening group.

Adult↗
PubMed2004

Primary sclerosing epithelioid fibrosarcoma of the sacrum: a case report and review of the literature.

Sclerosing epithelioid fibrosarcoma is a rare tumour characterised histologically by a predominant population of epithelioid cells arranged in strands and nests, embedded in a fibrotic and hyalinised stroma. It is a low grade tumour with an indolent course. A 48 year old woman presented with a painful swelling over her back for six months. Investigation and biopsy revealed features of sclerosing epithelioid fibrosarcoma involving the left half of the sacrum, left sacro-iliac joint, and posterior part of the left ilium. Preoperative radiotherapy and wide location excision of the tumour were followed by metastatic recurrence of the tumour in the lung and scalp six years after initial presentation. The tumour showed typical histology of sclerosing epithelioid fibrosarcoma. The radiological features confirmed its primary location in the sacrum. The patient declined chemotherapy and died of disseminated disease eight years after initial presentation. Review of the literature confirms the fact that sclerosing epithelioid fibrosarcoma, despite its low grade, is a clinicopathologically distinct tumour with full malignant potential, the recurrence, metastasis, and mortality rate being 48%, 60%, and 35%, respectively. Sclerosing epithelioid fibrosarcoma can occur as a primary bone tumour, the clinical behaviour of which is probably similar to its soft tissue counterpart.

Fatal Outcome↗
PubMed2003

Assessment of the efficacy of Proguard RR-2 radio-protective gloves during forearm manipulation.

The hazards of ionising radiation are well known and precautions, such as lead aprons and thyroid shields are routinely used. Orthopaedic surgeon's hands are at particular risk from direct and scatter radiation, when manipulating forearm fractures, due to the proximity of the image intensifier. The use of lead gloves has been recommended in the literature but are seldom employed. Proguard RR-2 gloves provide similar tactile sensitivity to double gloves and are claimed by the manufacturer to provide up to 55% protection in vitro at a direct beam energy level of 60 kV. This claim was tested in a clinical setting. The gloves were worn during forearm manipulations and the radiation dose measured using thermoluminescent dosimeters (TLDs). The results demonstrated a radiation attenuation of 60-64%. These gloves appear to achieve a good compromise between protection and sensitivity and should be included in routine protection against ionising radiation during MUA.

Equipment Design↗
PubMed2001

The operative management of displaced intra-articular fractures of the calcaneum: a two-centre study using a defined protocol.

The management of intra-articular calcaneal fractures remains controversial with strong arguments supporting both conservative and operative management. This study assesses the results of open reduction and internal fixation (ORIF) of displaced intra-articular fractures of the calcaneum in two independent centres where the indications for operative management had been strictly defined.Forty-seven patients (51 fractures) who had sustained such injuries underwent an ORIF performed by one of the senior surgeons using the technique described by Eastwood et al. [JBJS 75-B(1993)189] All of the fractures were assessed by plain X-ray and CT scan and graded according to the Sanders classification [Clin. Orthop. 290(1993)97]. Patients were assessed at a minimum of 2 years post-surgery both clinically and with a standardised questionnaire based on that described by Kerr et al. [Injury 27(1996)35]. The mean age at operation was 42 and 50 years for the two centres, and the mean follow-up was 44 months. Seventy-six per cent of the patients were male. Eighty-eight per cent of the injuries were due to a fall from a height. Fifteen patients had contralateral foot/ankle injuries. Thirty-four of 46 patients were in employment at the time of the injury, 24 of these were in physical jobs and 20 sustained their injury whilst at work.Overall, the satisfaction rate was 90%. Ninety-four per cent of patients in work returned to work at a median of 6 months. Bilateral injuries were associated with a significantly poorer outcome as were those with heel pad pain. Delay to operation greater than 14 days was associated with a higher infection rate. Smoking was not related to infection rate.

Accidental Falls↗
PubMed2001

Kaposiform hemangioendothelioma: five patients with cutaneous lesion and long follow-up.

Kaposiform hemangioendothelioma is a rare locally aggressive vascular tumor of the skin, deep soft tissue, and bone in children, characterized by infiltrating nodules and sheets of spindle cells, and unmistakable resemblance to Kaposi's sarcoma. More than 60 patients with such tumor have been reported so far, and while many have died as a result of extensive disease and severe coagulopathy, the long-term biologic behavior of this tumor remains undetermined. We describe five patients with kaposiform hemangioendothelioma and a mean follow-up of 19 years, ranging from 8 to 35 years. This report emphasizes on the importance of cutaneous lesions being the most commonly affected site, but also for its clinical diversity. Early diagnosis is possible even for a small skin lesion, which may be critical for the treatment of a potentially fatal deep-seated extensive tumor. All five patients are well, and three of them with persistent vascular tumor, which has carried two patients from childhood to adult. Although the behavior of this tumor might have been modified by radiation or interferon in three patients, this series indicates that kaposiform hemangioendothelioma is incapable of metastasis, despite a protracted course of many decades with no tendency for spontaneous regression.

Adult↗
PubMed2001

The effect of surgeon experience on component positioning in 673 Press Fit Condylar posterior cruciate-sacrificing total knee arthroplasties.

Component angles of 673 Press Fit Condylar (PFC) total knee arthroplasties were measured from standard short-leg radiographs. The femoral and tibial resections were performed with intramedullary and extramedullary instrumentation. The mean coronal tibial component angle was 88.59 degrees (SD, 2.28 degrees; range, 78-98 degrees ), with 17.1% having values <87 degrees and 1.9% having values >93 degrees. The mean coronal femoral component angle was 97.43 degrees (SD, 3.44 degrees; range, 84-115 degrees ), with 9.1% having values <94 degrees and 13.1% having values >100 degrees. An ideal tibiofemoral angle of 4 degrees to 10 degrees of valgus was achieved in 75.3% of patients, being <4 degrees in 18.6% and >10 degrees in 6.1%. Alignment was not significantly different between consultant and trainee surgeons. Although varus positioning of the tibial component was the commonest error, the wide range of femoral component angles signifies problems with standard intramedullary femoral guides.

Arthroplasty, Replacement, Knee↗
PubMed2001

Selected case from the Arkadi M. Rywlin International Pathology Slide Seminar: desmoplastic fibroblastoma (collagenous fibroma).

Desmoplastic fibroblastoma (collagenous fibroma) is a rare and recently described benign soft tissue tumor. It is more common in men, median age is 50 years, the history is usually long, and the usual size is around 3 cm. Most lesions are subcutaneous but approximately 25% involve skeletal muscle. Histologically, they are sparsely cellular with stellate and spindle-shaped fibroblasts-myofibroblasts that are separated by a collagenous or myxocollagenous matrix. Mitoses are minimal or absent. Tumor cells are focally positive for muscle-specific and alpha smooth muscle actins, and rarely, for keratins. The S-100 is usually negative but a very few cases have been positive. It can be confused with one of the fibromatoses, myxomas of various kinds and neural tumors. It neither recurs nor metastasizes.

Fibroma, Desmoplastic↗
PubMed2000

Triplane fracture of the distal tibia.

A prospective study of 21 triplane fractures of the distal tibia is presented. Nineteen cases (90.5%) had lateral triplane fractures, while the other two (9.5%) had medial triplane fractures. Two fragment fractures were encountered in 12 cases (57%); three fragment fractures in six cases (29%), and four fragment fractures in the remaining three cases (14%). Fourteen cases (67%) were managed non-operatively, while in seven cases (33%), open reduction and internal fixation was performed. Twenty patients (95%) were pleased with the final outcome. Objectively, 14 cases (67%) achieved excellent results.

Adolescent↗
PubMed2000

Myxoma is not a single entity: a review of the concept of myxoma.

Myxoid lesions can be subdivided into (1) mainstream myxomas of soft tissues, (2) mainstream myxomas located outside the soft tissue, (3) inadequately substantiated myxomas, (4) myxoid soft tissue tumors or lesions not regarded as myxomas, (5) myxoid fatty conditions, (6) other soft tissue lesions and tumors that are sometimes markedly myxoid, (7) other soft tissue tumors in which myxoid foci may be seen, and (8) nonneoplastic myxoid conditions of soft tissue. More than 60 such conditions are listed and the five entities regarded as mainstream soft tissue myxomas (namely, intramuscular myxoma, juxta-articular myxoma, superficial angiomyxoma, aggressive angiomyxoma, and myxoid neurothekeoma [myxoma of nerve sheath]) are reviewed in detail. Intramuscular myxoma is exclusively intramuscular, usually affects middle-aged women, is most commonly located in the thigh, and does not recur after simple excision. Multiple intramuscular myxomas are rare and are usually associated with monostotic or polyostotic fibrous dysplasia and Albright's syndrome. Juxta-articular myxoma histologically resembles an intramuscular myxoma, but involves periarticular tendons, ligaments, joint capsules, muscles, and even the subcutis of adults. It may be associated with osteoarthritis of the adjacent joint. Some 30% recur locally. Superficial angiomyxoma also has been called cutaneous myxoma. It affects all ages, with a peak incidence in the third and fourth decades; arises in the trunk, lower limb, head, and neck regions; and usually measures less than 5 cm in diameter. Epithelial components are present in approximately 25% of tumors. Approximately one third recur locally, but there have been no metastases. Patients with multiple lesions may have the Carney complex. Aggressive angiomyxoma usually arises in the pelvic and perineal regions and affects females seven times as often as males. Tumors usually measure 10 cm or more in diameter, invade surrounding tissues, and recur in approximately 50% of cases. None have metastasized. Myxoma of nerve sheath (the myxoid variant of neurothekeoma) preferentially affects the dermis and subcutis of the cervicofacial areas and shoulders of young women. Most patients are younger than 40 years; one third of them are in the second decade of life. The majority of tumors measure between 0.5 and 1.5 cm. Only three of 102 cases compiled from the two largest published series recurred; none metastasized. The different clinicopathologic features and behavior of these five mainstream myxomas indicate that myxoma is not a single entity.

Adult↗
PubMed1999

Carcinosarcoma of the parotid gland: ultrasound and computed tomography findings.

Carcinosarcoma is a rare tumour of the salivary gland. The ultrasound and CT appearances of a rapidly enlarging carcinosarcoma in the parotid are described. Both modalities revealed a 4-cm tumour with relatively benign features and no evidence of lymphadenopathy. Ultrasound showed a well-defined mass of homogeneous low echogenicity and posterior acoustic enhancement. Computed tomography showed a parotid mass of homogeneous attenuation similar to muscle, and homogeneous enhancement following contrast. The clue to the malignant nature of the lesion was a short indistinct superficial margin with tumour extension into the adjacent subcutaneous tissues.

Adult↗
PubMed1998

Adelaide's blackbirding pathologist.

Archibald Watson (1849-1940) was the inaugural Elder Professor of Anatomy at the University of Adelaide. He held the position from 1885 to 1919, having previously trained in Gottingen, Paris, and London under some of the most eminent physicians of those times. Before he started his medical studies, he, Dr James Patrick Murray, and several others were involved in the kidnapping ("blackbirding") of Pacific Islanders (Kanakas) to work on South Sea cotton plantations. A number of the victims were killed. Watson and two others were charged with murder and remanded in Levuka to appear in Sydney. Watson absconded, traveled to Europe, and never stood trial; the other two were convicted and sentenced to death. Watson's life as an anatomist, surgeon, pathologist, member of the Adelaide Club, world traveler, Australian Army doctor during the Boer War and World War I, fisherman, and motorcyclist was full of interest and incidents. The events surrounding the autopsy he performed on a case of fibrodysplasia ossificans progressiva and the subsequent preservation of the skeleton in the Anatomy Museum of the University of Adelaide are described.

Anatomy↗
PubMed1998

Atypical subcutaneous fatty tumors: a review of 37 referred cases.

We reviewed 37 referred, atypical, subcutaneous fatty tumors. There was a male preponderance (28:9). The median age was 51.5 years (26-83); the median duration of symptoms was 18 months (three weeks to 35 years); the median size was 5.5 cm (1.5-20) and the posterior cervico-dorsal areas (17 cases) was the commonest location. We divided tumors into five histological categories: (1) subcutaneous fibrolipomas with slight fibroblastic atypia (five cases); (2) subcutaneous spindle cell lipomas with atypia (mixed spindle cell/pleomorphic lipomas) without lipoblasts (three cases); (3) subcutaneous atypical well-differentiated fatty tumors (pure pleomorphic lipomas) without lipoblasts (nine cases); (4) subcutaneous atypical well-differentiated fatty tumors (pleomorphic lipomas) with lipoblasts (17 cases); (5) subcutaneous atypical fatty tumors with poorly differentiated or de-differentiated areas (three cases). Follow-up information was obtained in 25 cases (68%). The follow-up times were from three to 192 months (median 31). Five tumors (20%) recurred, two as the same and three as a higher histological category. Two were originally referred because of a recurrence. Four recurred once and one, initially a category 4 tumor, recurred twice as a category 5 tumor. Two category 1 and three category 4 tumors recurred. There were no recurrences in the other three groups. All recurrent tumors were located outside the cervico-dorsal areas. The sizes of two tumors that recurred were 2.8 and 3 cm and the time to first recurrence was from one to 85 months. Two recurrent tumors of high histological category were controlled by re-excision and either radiotherapy or combined chemotherapy and radiotherapy. This series suggests that atypical subcutaneous fatty tumors comprise a continuous and potentially transforming histological spectrum, which ranges from mildly atypical fibrolipomas through various mixed spindle cell and pleomorphic lipoma patterns to tumors indistinguishable from de-differentiated liposarcomas. Despite a sometimes alarming histological appearance, none in the present series metastasized.

Adult↗
PubMed1998

Carcinoma showing thymiclike differentiation (CASTLE tumor).

A 67-year-old woman had had a neck mass for 10 years, which recently increased in size. Sonographic, CT, and MR examinations showed a mass in the carotid and posterior spaces (triangle) extending from below the submandibular gland to the supraclavicular fossa, displacing the common carotid artery and the sternomastoid anteriorly. The mass was solid, noncalcified with lobulated outlines, hypoechoic on sonograms, of soft-tissue density on CT scans, isointense on T1-weighted MR images, hyperintense on T2-weighted MR images, and enhanced mildly after injection of contrast material on CT and MR studies. Histologic examination revealed a carcinoma showing thymiclike differentiation, a rare tumor of the neck and thyroid gland.

Aged↗