Chicken wings and the brachial plexus.

OBJECTIVES: Some stages of limb development can now be described in terms of gene sequences and functions. This paper reports on the development of the brachial plexus (BP) in the chick. It also presents a short review on the principles of the peripheral nerve outgrowth. METHODS: The early development of the brachial plexus of chicken embryos is mapped using immunohistochemistry. This is then analysed in relation to the expression pattern of an axonal guidance gene, Semaphorin3a, by in situ hybridization studies. RESULTS: The motor axons that innervate the chick wing emerge from the spinal cord in spinal nerves 12-17. These axons grow towards the developing limb and then congregate at its base to form the plexus. In response to unknown cues, these axons rearrange, before emerging in the defined nerve trunks that innervate the limb. The developmental stages of BP morphogenesis described here closely correlate with previous reports with a significant difference of a shorter 'waiting period'. DISCUSSION: The development of the brachial plexus is now better understood. The waiting period, with more modern techniques, is observed to be shorter than previously reported. The significance of this and the role of the guidance molecule, Semaphorin3a, in this process, are being investigated and the results may have important implications on the management of brachial plexus palsy and other peripheral nerve lesions.

Clinical diagnosis of skin tumours: how good are we?

BACKGROUND: Few studies have addressed the accuracy of clinical diagnosis of skin malignancies. The present prospective study aims to determine the accuracy with which these lesions are diagnosed and attempts to identify the factors influencing the accuracy of clinical diagnosis. METHODS: All patients undergoing surgical excision of a skin cancer with curative intent from January 2001 to December 2002 at Peter MacCallum Cancer Institute, Melbourne, Australia were prospectively studied. Data were entered into the Filemaker Pro program and analysed using the SPSS software package. RESULTS: A total of 2582 lesions were surgically excised from 1223 patients. Of these 47% were basal cell carcinomas (BCC), 20% were squamous cell carcinomas (SCC), 0.9% were malignant melanomas (MM), and 32.1% were benign or premalignant. Tumours, benign and malignant, were found to be more common in men. The sensitivity for clinical diagnosis of malignancy was 97.5% while the positive predictive value (PPV) for clinical diagnosis of malignancy was 70.3%. BCC and SCC was diagnosed with a sensitivity of 89% and 56.3%, and PPV of 64.5% and 40.3%, respectively (P < 0.001). 23 MM were excised with a sensitivity of clinical diagnosis of 47.8% and PPV of 30.6%. Sensitivity and PPV were also assessed according to clinical experience of the surgeon, site of the lesion and whether surgery was performed for a primary or a recurrent lesion. Sensitivity and PPV were higher for lesions diagnosed by consultant surgeons when compared with surgical trainees (P < 0.001) - MM was diagnosed with a sensitivity of 100% by consultant surgeons. CONCLUSION: The present study shows sensitivity and PPV rates comparable to published figures.

Incomplete excision of basal cell carcinomas: a retrospective audit.

BACKGROUND: The reported rates of incomplete excision of basal cell carcinoma (BCC) vary widely (5-25%) among centres around the world. Incomplete excision of skin malignancy is one of the 57 clinical indicators developed by the Royal Australasian College of Surgeons and the Australian Council on Healthcare Standards to act as a measure of the standard of surgical care. The study aims to determine the rate of incomplete excision of BCC at a major cancer centre. METHODS: Computerized data and patients' records were reviewed. From January 1997 to June 2000, a total of 3558 BCC were surgically excised with curative intent, of which 223 were reported to have been removed incompletely. RESULTS: The overall rate of incomplete excision was 6.3%. CONCLUSIONS: Given the limitations of a retrospective audit and reliability of the data, this result nevertheless compares favourably with reported figures in the literature.

Too much vacuum-assisted closure.

There has been an explosion in the use of the vacuum-assisted closure device since 1997. Selectively and judiciously used, it is a valuable tool. However, we are concerned by the expanding list of 'indications' for its use. Prolonged applications, frequently several weeks, at the expense of early surgical reconstruction, might compromise the outcome in selected cases. We report four cases that illustrate this problem and stress the importance of timely surgical reconstruction utilizing the range of reconstructive techniques available as well as vacuum-assisted closure dressing.

Negative pressure pulmonary edema in healthy cosmetic surgery patients.

Anesthetic complications are uncommon in young and healthy patients undergoing cosmetic surgery. We report 2 cases of negative pressure pulmonary edema (NPPE) in young patients, 1 who underwent rhinoplasty and another who underwent augmentation mammaplasty and suction-assisted lipoplasty of the thighs and buttocks This rare and potentially fatal complication requires admission to an intensive-care unit and delayed discharge. Although cases of NPPE have been reported in the medical and anesthetic literature, NPPE in plastic surgery has never been reported previously.

Incomplete excision of basal cell carcinoma: a prospective trial.

BACKGROUND: As a measure of the standard of surgical care, incomplete excision of skin malignancy is an important clinical indicator, developed by the Royal Australasian College of Surgeons and the Australian Council on Healthcare Standards. Reported rates of incomplete excision of basal cell carcinoma vary widely (5 to 25 percent) among centers worldwide. This prospective study reports on the incidence of incomplete excision at a tertiary referral public hospital and determines the factors that may influence this. METHODS: From January of 2001 to December of 2002, 1214 basal cell carcinomas were excised at Peter MacCallum Cancer Centre. Data were collected prospectively and analyzed using the FileMaker Pro program and SPSS software. RESULTS: The overall percentage of incomplete excision was 11.2 percent for primary excisions. Risk factors for incomplete excision are the head site; morpheic, superficial, and infiltrative subtypes; lesions larger than 20 mm in diameter; the presence of multiple lesions; repair by skin graft; and recurrent and previously incompletely excised basal cell carcinomas. The type of anesthetic used did not affect outcome. There was no significant difference in the percentage of incomplete excision between consultants, registrars, and the clinical assistant, but this was probably attributable to the small number of cases performed by consultants at Peter MacCallum Cancer Centre. CONCLUSIONS: This is the largest prospective study of incomplete excision of basal cell carcinomas. The authors' result is within the range reported in the current literature but is higher than anticipated. Preoperative "red-flagging" of basal cell carcinomas most at risk of incomplete excision may lead to a better result.

Incomplete excision of squamous cell carcinoma of the skin: a prospective observational study.

BACKGROUND: Squamous cell carcinoma is the second most common cancer of the skin. It behaves differently from basal cell carcinoma. Few large-scale studies have identified risk factors for incomplete excision of cutaneous squamous cell carcinoma. The authors report the largest prospective study to identify the risk factors for incomplete excision of these lesions. METHODS: A total of 517 histopathologically confirmed squamous cell carcinomas were excised from January of 2001 to December of 2002 at the Peter MacCallum Cancer Institute. Of these, 480 primary excisions were analyzed. Data pertaining to patient age, sex, lesion size, margin of excision, recurrence, previous excision, site, anesthetic choice, and repair method were collected prospectively. RESULTS: The overall incomplete excision rate was 6.3 percent. Lesions on the ear (p < 0.003), re-excisions (p < 0.001), and invasive lesions (p < 0.001) were associated with the highest incomplete resection rates. Age (p = 0.61), sex (p = 0.075), tumor size (p = 0.521), surgeon's experience (p = 0.092), and recurrent lesions (p = 0.408) were not statistically significant risk factors. CONCLUSIONS: Statistically significant risk factors were ear lesions, invasive lesions, and previously incompletely excised lesions referred for re-excision. The authors recommend more care with tumor markings, taking margins of at least 5 mm, using deeper margins, and referring patients to more experienced centers.

Genes and nerves.

The unpredictability of a brachial plexus graft, a median nerve repair, or a facial-nerve reconstruction is well known. No matter how precise the technical skills, a perfect recovery from a peripheral-nerve lesion is elusive. To resolve this problem, understanding of the normal development of the peripheral nervous system is needed. Presently, the development of the innervation in the upper limb is complex and not fully understood. However, many of the genes involved in this process are now known, and the link between anatomy and genetics is becoming clearer. This short review aims to acquaint the clinical surgeon with some of the main genes. The principal steps in the establishment of neural circuits will be summarized, in particular, the specification and development of neurons and glia, the pathfinding of cells and axons towards their target, and the downstream molecules that control the circuitry of these neurons.