Surgical aspects and future developments of laparoscopy

Laparoscopy has revolutionized surgery and in the process influenced the practice of anesthesiology. This article reviews several minimal access procedures that have been accepted into practice, are gaining acceptance, or remain investigational. Absolute contraindications to laparoscopy have been emphasized. As the threshold for primary care physicians to refer sicker and sicker patients for surgery decreases, it is crucial for the anesthesiologist to understand physiologic stresses of pneumoperitoneum and the nuances of laparoscopic surgery. The anesthesiologist also can be recruited to adjust insufflation pressures, tweak images on monitors, rotate and position the patient, or pass balloons and bougies. With patient and surgeon expectation of no pain or nausea and early discharge, anesthetic choices become vital for the ultimate success of the procedure.

Accuracy and effectiveness of laparoscopic vs open hepatic radiofrequency ablation

BACKGROUND

The purpose of this study was to compare the accuracy (in terms of ultrasound-guided probe placement) and the effectiveness (in terms of pathologic tumor-free margin) of laparoscopic vs open radiofrequency (RF) ablation.

METHODS

Using a previously validated tissue-mimic model, 1-cm simulated hepatic tumors were ablated in 10 pigs randomized to open or laparoscopic techniques. Energy was applied until tissue temperature reached 100 degrees C (warm-up) and thereafter for 8 min. A pathologist blinded to technique examined all specimens immediately after treatment. Analysis was by Fisher's exact test and the Mann-Whitney U test; p < 0.05 was considered significant.

RESULTS

Off-center distance (3.5 +/- 1.6 vs 4.2 +/- 1.4 mm), size (24.7 +/- 3.1 vs 25.6 +/- 3.8 mm), symmetry (40% vs 73%), margin positivity (33% vs 9%), and margin distance (1.1 +/- 1.2 vs 2.2 +/- 1.6 mm) were not significantly different between laparoscopic (n = 15) and open (n = 11) ablations, respectively. The proportion of round/ovoid lesions (20% vs 64%) was lower (p = 0.043), and warm-up time (20.2 +/- 14.0 vs 10.7 +/- 7.5) was longer (p = 0.049) for the laparoscopic than for the open groups, respectively.

CONCLUSION

Accurate probe placement can be achieved using laparoscopic and open RF ablation techniques. The physiologic effects of laparoscopy may alter ablation shape and warm-up time. Additional studies are needed to establish effective ways of achieving complete tumor destruction.

Curvularia keratitis

PURPOSE

To determine the risk factors and clinical signs of Curvularia keratitis and to evaluate the management and outcome of this corneal phaeohyphomycosis.

METHODS

We reviewed clinical and laboratory records from 1970 to 1999 to identify patients treated at our institution for culture-proven Curvularia keratitis. Descriptive statistics and regression models were used to identify variables associated with the length of antifungal therapy and with visual outcome. In vitro susceptibilities were compared to the clinical results obtained with topical natamycin.

RESULTS

During the 30-year period, our laboratory isolated and identified Curvularia from 43 patients with keratitis, of whom 32 individuals were treated and followed up at our institute and whose data were analyzed. Trauma, usually with plants or dirt, was the risk factor in one half; and 69% occurred during the hot, humid summer months along the US Gulf Coast. Presenting signs varied from superficial, feathery infiltrates of the central cornea to suppurative ulceration of the peripheral cornea. A hypopyon was unusual, occurring in only 4 (12%) of the eyes but indicated a significantly (P = .01) increased risk of subsequent complications. The sensitivity of stained smears of corneal scrapings was 78%. Curvularia could be detected by a panfungal polymerase chain reaction. Fungi were detected on blood or chocolate agar at or before the time that growth occurred on Sabouraud agar or in brain-heart infusion in 83% of cases, although colonies appeared only on the fungal media from the remaining 4 sets of specimens. Curvularia was the third most prevalent filamentous fungus among our corneal isolates and the most common dematiaceous mold. Corneal isolates included C senegalensis, C lunata, C pallescens, and C prasadii. All tested isolates were inhibited by 4 micrograms/mL or less of natamycin. Topical natamycin was used for a median duration of 1 month, but a delay in diagnosis beyond 1 week doubled the average length of topical antifungal treatment (P = .005). Visual acuity improved to 20/40 or better in 25 (78%) of the eyes.

CONCLUSIONS

Curvularia keratitis typically presented as superficial feathery infiltration, rarely with visible pigmentation, that gradually became focally suppurative. Smears of corneal scrapings often disclosed hyphae, and culture media showed dematiaceous fungal growth within 1 week. Natamycin had excellent in vitro activity and led to clinical resolution with good vision in most patients with corneal curvulariosis. Complications requiring surgery were not common but included exophytic inflammatory fungal sequestration, treated by superficial lamellar keratectomy, and corneal perforation, managed by penetrating keratoplasty.

Immune thrombocytopenic purpura during pregnancy: laparoscopic treatment

BACKGROUND AND OBJECTIVES

Laparoscopic surgical techniques in pregnancy have been accepted and pose minimal risks to the patient and fetus. We present the first reported case of a pregnant woman with immune thrombocytopenia purpura who underwent laparoscopic splenectomy during the second trimester.

METHODS AND RESULTS

The anesthesia, hematology, and obstetrics services closely followed the patient's preoperative and intraoperative courses. After receiving immunization, stress close steroids, and prophylactic antibiotics, she underwent a successful laparoscopic splenectomy. After a short hospital stay, the patient was discharged home.

CONCLUSION

Immune thrombocytopenia purpura can be an indication for splenectomy. As demonstrated in appendectomy, cholecystectomy, and our case presentation, laparoscopic splenectomy can be safely performed during pregnancy.

Microsphaeropsis olivacea keratitis and consecutive endophthalmitis

PURPOSE

To report a case of fungal keratitis with consecutive endophthalmitis caused by Microsphaeropsis olivacea.

METHODS

Case report.

RESULTS

A 51-year-old man developed fungal keratitis and consecutive endophthalmitis after sustaining a penetrating injury to the right eye. Cultures of the aqueous humor yielded M. olivacea. Infection resolved after intraocular fungal debridement, intravitreous amphotericin B, and aggressive topical natamycin and oral fluconazole. Persistent, low-grade smoldering corneal and intraocular inflammation required topical corticosteroid therapy.

CONCLUSION

M. olivacea is an exceedingly rare ocular pathogen. The intraocular portion of the infection responded quickly to intravitreal antifungal treatment; however, the course was prolonged by smoldering corneal inflammation. Prompt recognition of intraocular spread and aggressive treatment may be beneficial in fungal infections caused by unusual organisms with uncertain virulence.

Development of an in vivo tumor-mimic model for learning radiofrequency ablation

Radiofrequency ablation requires accurate probe placement using ultrasound guidance. The purpose of this study was to develop an in vivo tumor-mimic model for learning open and laparoscopic radiofrequency ablation. Tumor-mimics were created in ex vivo porcine livers by injecting a mixture of 3% agarose, 3% cellulose, 7% glycerol, and 0.05% methylene blue, which formed 1 cm hyperechoic, discrete lesions on ultrasound. Open and laparoscopic (using a box-trainer) ablation techniques were practiced. In vivo experiments were then conducted in 10 pigs. Three tumor-mimics were created in each animal using a laparoscopic approach. Lesions were characterized sonographically, ablated using an open (n = 5) or laparoscopic (n = 5) approach, and examined pathologically. An ablation in normal liver tissue was performed as a control. Tissue impedance was recorded. Target creation took 81 minutes per animal and 96% of injections were successful. Tissue impedance (48.8 +/- 5.8 vs. 49.6 +/- 5.4) and ablation size (25.1 +/- 3.4 vs. 24.3 +/- 5.1) were not significantly different for controls (n = 8) and tumor-mimics (n = 26), respectively. One animal died of a pulmonary embolism following injection of agarose into a hepatic vein. The agarose-based tissue-mimic creates realistic sonographic targets for learning ultrasound-guided open and laparoscopic radiofrequency ablation in an in vivo model.

Evaluating surgical competency with the American Board of Surgery In-Training Examination, skill testing, and intraoperative assessment

BACKGROUND

Evaluation of surgical competency should include assessment of knowledge, technical skill, and judgment. The purpose of this study was to determine the relationship between the American Board of Surgery In-Training Examination (ABSITE), skill testing, and intraoperative assessment.

METHODS

Postgraduate year 2 (PGY-2) and postgraduate year 3 (PGY-3) surgery residents (n = 33) were tested by means of (1) the ABSITE, (2) skill testing on a laparoscopic video-trainer, and (3) intra-operative global assessments during laparoscopic cholecystectomy. The Pearson correlation was used to determine the correlation between the ABSITE, skill testing, and intraoperative assessments. For the comparison of PGY-2 and PGY-3 resident performance, Wilcoxon rank sum tests were used.

RESULTS

The ABSITE scores did not correlate with skill testing or intraoperative assessments (not significant). Skill testing correlated with the intraoperative composite score and with 4 of 8 operative performance criteria (P<.05). The ABSITE scores and skill testing were not different for PGY-2 and PGY-3 residents (not significant). Intraoperative assessments were better in 5 of 8 criteria and the composite score for PGY-3 versus PGY-2 residents (P<.05), which demonstrated construct validity.

CONCLUSIONS

The ABSITE measures knowledge but does not correlate with technical skill or operative performance. Residency programs should use multiple assessment instruments to evaluate competency. There may be a role for both skill testing and intraoperative assessment in the evaluation of surgical competency.

Laparoscopic training on bench models: better and more cost effective than operating room experience?

BACKGROUND

Developing technical skill is essential to surgical training, but using the operating room for basic skill acquisition may be inefficient and expensive, especially for laparoscopic operations. This study determines if laparoscopic skills training using simulated tasks on a video-trainer improves the operative performance of surgery residents.

STUDY DESIGN

Second- and third-year residents (n= 27) were prospectively randomized to receive formal laparoscopic skills training or to a control group. At baseline, residents had a validated global assessment of their ability to perform a laparoscopic cholecystectomy based on direct observation by three evaluators who were blinded to the residents' randomization status. Residents were also tested on five standardized video-trainer tasks. The training group practiced the video-trainer tasks as a group for 30 minutes daily for 10 days. The control group received no formal training. All residents repeated the video-trainer test and underwent a second global assessment by the same three blinded evaluators at the end of the 1-month rotation. Within-person improvement was determined; improvement was adjusted for differences in baseline performance.

RESULTS

Five residents were unable to participate because of scheduling problems; 9 residents in the training group and 13 residents in the control group completed the study. Baseline laparoscopic experience, video-trainer scores, and global assessments were not significantly different between the two groups. The training group on average practiced the video-trainer tasks 138 times (range 94 to 171 times); the control group did not practice any task. The trained group achieved significantly greater adjusted improvement in video-trainer scores (five of five tasks) and global assessments (four of eight criteria) over the course of the four-week curriculum, compared with controls.

CONCLUSIONS

Intense training improves video-eye-hand skills and translates into improved operative performance for junior surgery residents. Surgical curricula should contain laparoscopic skills training.

Measuring operative performance after laparoscopic skills training: edited videotape versus direct observation

BACKGROUND AND PURPOSE

Global assessment by direct observation has been validated for evaluating operative performance of surgery residents after formal skills training but is time-consuming. The purpose of this study was to compare global assessment performed from edited videotape with scores from direct observation.

MATERIALS AND METHODS

Junior surgery residents (N = 22) were randomized to 2 weeks of formal videotrainer skills training or a control group. Laparoscopic cholecystectomy was performed at the beginning and end of the rotation, and global assessment scores were compared for the training and control groups. Laparoscopic videotapes were edited: initial (2 minutes), cystic duct/artery (6 minutes), and fossa dissection (2 minutes). Two independent raters performed both direct observation and videotape assessments, and scores were compared for each rater and for interrater reliability using a Spearman correlation.

RESULTS

Correlation coefficients for videotape versus direct observation for five global assessment criteria were <0.33 for both raters (NS for all values). The correlation coefficient for interrater reliability for the overall score was 0.57 (P = 0.01) for direct observation v 0.28 (NS) for videotape. The trained group had significantly better overall performance than the control group according to the assessment by direct observation (P = 0.02) but not by videotape assessment (NS).

CONCLUSIONS

Direct observation demonstrated improved overall performance of junior residents after formal skills training on a videotrainer. Global assessment from an edited 10-minute videotape did not correlate with direct observation and had poor interrater reliability. Efficient and valid methods of evaluating operative performance await development.

Laparoscopic Roux-en-Y gastric bypass: transoral or transgastric anvil placement?

BACKGROUND

Laparoscopic techniques have been used to perform the Roux-en-Y gastric bypass (RYGBP). The gastrojejunostomy may be constructed using an end-to-end anastomosis (EEA) stapler. Most reports describe passing the EEA anvil transorally using an esophagogastroscope and a pull-wire technique.

METHOD

We describe problems experienced using this technique and present an alternative method.

RESULTS

Esophageal injury may occur during laparoscopic RYGBP (LRYGBP) using the transoral anvil placement technique. When the anvil is retrieved into the gastric pouch, the anvil may become lodged at the cricopharngeus muscle. Dislodgment can be problematic and time-consuming. We present a case of mild esophageal injury which occurred during transoral anvil placement. The patient had transient postoperative dysphagia and recovered without sequelae. We present an alternative method in which the anvil is passed through a gastrotomy.

CONCLUSION

Transgastric anvil placement alleviates the need for endoscopy, thereby saving time and resources. This technique eliminates the potential for esophageal injury. The transgastric anvil placement technique has proven reliable. The transgastric method may make the LRYGBP operation safer and easier to perform.

Selective genetic analysis of p53 immunostain positive cells

The isolation of p53 immunostain positive cells from histological sections for molecular genetic studies is a difficult task, especially if there are few positive cells. To eliminate contaminating DNA from p53 negative cells, which can obscure the results of molecular assays, a variation on the technique of immunohistoselective sequencing was developed. This is a highly selective approach, whereby immunostained sections of formalin fixed, paraffin wax embedded tissue are exposed to ultraviolet irradiation to damage the DNA in p53 negative cells. The DNA in positive cells remains unaffected because the dark immunostain protects their nuclei from ultraviolet light. Polymerase chain reaction single strand conformation polymorphism of samples enriched with p53 immunostain positive cells has shown that this method can produce pure samples of mutated DNA. The isolation of DNA from minority immunostain positive cells allows a wide range of molecular analyses to be carried out on these samples, which would otherwise be hampered by the problem of contaminating background cells.

The collagen-binding adhesin is a virulence factor in Staphylococcus aureus keratitis

A collagen-binding strain of Staphylococcus aureus produced suppurative inflammation in a rabbit model of soft contact lens-associated bacterial keratitis more often than its collagen-binding-negative isogenic mutant. Reintroduction of the cna gene on a multicopy plasmid into the mutant helped it regain its corneal adherence and infectivity. The topical application of a collagen-binding peptide before bacterial challenge decreased S. aureus adherence to deepithelialized corneas. These data suggest that the collagen-binding adhesin is involved in the pathogenesis of S. aureus infection of the cornea.

Aspartate aminotransferase: alanine aminotransferase ratio in chronic hepatitis C infection: is it a useful predictor of cirrhosis?

BACKGROUND

The clinical usefulness of the ratio of serum aspartate aminotransferase (AST) to alanine aminotransferase (ALT) has been explored in several liver disorders. It has been suggested that in patients with chronic hepatitis C virus (HCV) infection an AST:ALT > or = 1 has 100% specificity and positive predictive value in distinguishing cirrhotic from non-cirrhotic patients. Such statistical certainty attached to a simple biochemical test merits further evaluation. The present study, therefore, assessed the AST:ALT in patients with chronic HCV infection to determine the validity of the ratio in predicting cirrhosis and to correlate the ratio with the histological grade of necroinflammatory activity and fibrosis.

METHODS

A retrospective analysis of 153 patients with chronic HCV infection was conducted. Serum biochemistry had been obtained within a mean of 4 weeks of liver biopsy. The histology was scored in terms of activity and fibrosis as described by Scheuer and correlated with AST:ALT.

RESULTS

In 30 patients with cirrhosis, the mean AST:ALT (0.99 +/- 0.06) was higher than in 123 patients without cirrhosis (0.60 +/- 0.02; P < 0.001). A ratio > or = 1 had 95.9% specificity and 73.7% positive predictive value in distinguishing cirrhotic from non-cirrhotic patients, with a 46.7% sensitivity and 88.1% negative predictive value. The ratio also parallelled the Scheuer score with respect to fibrosis but not with respect to inflammation.

CONCLUSION

Although relatively insensitive, an AST:ALT > or = 1 is highly specific but not diagnostic for the presence of cirrhosis in patients with chronic HCV infection. The ratio reflects the grade of fibrosis in these patients.

Epstein-Barr virus dacryoadenitis

PURPOSE

To describe the clinical features of lacrimal gland inflammation associated with Epstein-Barr virus infection.

METHODS

The clinical records, laboratory data, and radiographs of patients who had inflammation of one or both lacrimal glands that had begun less than 4 weeks previously were reviewed.

RESULTS

Sixteen patients with dacryoadenitis were encountered between 1980 and 1996, a cumulative frequency of approximately one case per 10,000 new ophthalmic outpatients. Six individuals had serologic or other evidence of recent Epstein-Barr virus infection and were distinguished by the presence of regional lymphadenopathy, no purulent discharge, and a duration of symptoms of 6 weeks.

CONCLUSION

Epstein-Barr virus is a probable cause of unilateral and bilateral dacryoadenitis in young adults.

Amplification of PCR products in excess of 600 base pairs using DNA extracted from decalcified, paraffin wax embedded bone marrow trephine biopsies

AIMS

To establish a robust method of extracting DNA from paraffin wax embedded bone marrow trephine (PBMT) biopsies for the amplification of relatively long polymerase chain reaction (PCR) products.

METHOD

Xylene and ethanol were used to remove paraffin wax from eight formalin fixed, EDTA decalcified PBMT biopsies and DNA extraction was performed using a Qiagen QIAamp tissue kit. The DNA samples were amplified using nine different PCR primers sets, including those used to detect chromosomal translocations (t(11;14) and t(14;18), and clonal B cell populations. A t(11;14) PCR product of approximately 600 base pairs (bp) was sequenced using dye terminator cycle sequencing.

RESULTS

All eight DNA samples extracted from PBMT biopsies were amplified successfully to generate DNA fragments up to 643 bp in length. Chromosomal translocations and immunoglobulin gene rearrangements were detected by PCR in some of the samples. Sequencing of the t(11;14) PCR product demonstrated the presence of chimaeric sequences, which included both bcl-1 and immunoglobulin heavy chain (IgH) gene sequences, consistent with the presence of this translocation.

CONCLUSIONS

This method enables PCR analyses of PBMT biopsies that were not previously possible, offering the prospect of improved accuracy of diagnosis and the monitoring of patients with bone marrow disease.

Impact of amino acid nutrition during lactation on body nutrient mobilization and milk nutrient output in primiparous sows

The impact of amino acid nutrition during lactation on body nutrient mobilization and milk nutrient output in primiparous sows was evaluated. Thirty-six sows, nursing litters of 13 pigs, were allocated daily 6 kg of a fortified corn-soybean meal diet containing a high (HP, 1.20% lysine) or low (LP, .34% lysine) protein content during a 23-d lactation. Dietary lysine concentration was achieved by altering the ratio of corn and soybean meal in the diet. The LP sows consumed less daily ME (14.2 vs 16.1 Mcal; P < .11) and daily lysine (16 vs 59 g; P < .01) than the HP sows. Daily litter weight gain was less (P < .01) for sows fed the LP vs HP diet, and the differences increased (P < . 01) as lactation progressed. The lower litter weight gain for the LP sows was reflective of the lower (P < .01) estimated milk DM, CP, and GE output of these sows. The LP sows lost more body weight (1.23 vs .21 kg/d; P < .01) during the initial 20 d of lactation. In the LP sows, 59% of the weight loss was protein, water, and ash, and 37% was fat. Weight loss in the HP sows was entirely accounted for by body fat mobilization, because these sows accrued body protein, water, and ash. Muscle myofibrillar breakdown rate was higher in LP sows than in HP sows (4.05 vs 2.80%/d; P < .01). On the basis of these data, dietary amino acid restriction during lactation increases maternal mobilization of proteinaceous tissue and reduces milk nutrient output. Maternal protein mobilization is maintained over the entire lactation even though milk output is decreased as lactation progresses.

Impact of amino acid nutrition during lactation on luteinizing hormone secretion and return to estrus in primiparous sows

The impact of the dietary amino acid regimen of primiparous sows on LH secretion and weaning-to-estrus interval was evaluated. Thirty-six sows, nursing litters of 13 pigs, were allocated daily 6 kg of a corn-soybean meal diet containing a high (HP, 1.20% lysine) or low (LP, .34% lysine) protein content during a 23-d lactation. Dietary lysine concentration was achieved by altering the ratio of corn and soybean meal in the diet. Plasma LH, ACTH, and estradiol-17beta were evaluated at 15 min, hourly, and at 6-h intervals, respectively, during 6-h periods on d 0, 5, 10, 15, and 20 of lactation. Sows were checked daily for estrus from weaning to 45 d postweaning. Sows fed the LP and HP diets consumed 4.41 and 4.98 kg of feed daily during lactation. The LP sows weighed less (P < .05), had lighter (P < .05) litters at weaning, and had (P < .05) extended weaning-to-estrus intervals. Mean and baseline LH concentrations and LH pulses/6 h were lower (P < .01) in LP sows, and the differences between LP and HP sows were established by d 10 of lactation. Plasma estradiol and ACTH concentrations were not altered by diet. Mean LH concentrations on d 5 and 10 of lactation were correlated (r = -.54 and -.56, respectively, P < .01) with weaning-to-estrus interval. Also, mean LH concentrations on d 10 were correlated (P < .05) with the magnitude of dietary lysine deficiencies relative to demand for milk synthesis on d 0 to 5 and d 5 to 10 (r = -.39 and -.49, respectively). Inadequate dietary amino acid intake in sows during early lactation results in lower LH secretion by d 10 postpartum and is associated with increased weaning-to-estrus interval.

Videoendoscopic thyroidectomy: experimental development of a new technique

Applications of minimally invasive surgery have evolved from laparoscopic cholecystectomy and spread beyond conventional body cavities to new applications and disease processes. The purpose of the present study was to evaluate the feasibility of performing videoendoscopic thyroidectomy in a canine model. Adult mongrel dogs served as the experimental model for this study. The pretracheal space was entered via a 2.5-cm midline neck incision superior to the sternal notch and then expanded with a balloon spacemaker. A mechanical lift device was used to maintain exposure, and a 12-mm midline cervical port and two lateral 5-mm cervical ports were placed. Dissection was carried out with pediatric endoscopic instruments, and hemostasis was obtained with endoscopic clips and an ultrasonic coagulator. Histologic analysis of the excised tissue was performed in all cases. Mean operative time for thyroid lobectomy was 69 minutes (range 58 to 99). The laryngeal nerves and external parathyroid glands were identified endoscopically in all cases. Blood loss was minimal. No complications were observed intraoperatively or during 1 week of postoperative follow-up. Serum calcium levels were stable. No wound hematomas, laryngeal nerve injuries, or other complications occurred. On average 16 mL (range 2 to 65) of seroma fluid was present in the pretracheal space at autopsy. In conclusion, a videoendoscopic approach to thyroid lobectomy is feasible in an animal model and provides adequate visualization of the important anatomy relevant to this procedure. These techniques may be applicable to thyroidectomy in humans and may impact on minimally invasive surgery in other nontraditional locations.

What is adequate training and competence in gastrointestinal endoscopy?

The Conjoint Committee for Recognition of Training in Gastrointestinal Endoscopy has published principles for endoscopic training. Despite this, views and objectives conflict between the various parent bodies and the Committee on how endoscopists should be trained, what constitutes adequate training and how competence should be maintained. Perhaps it is time to examine these issues critically.

Oral health assessment by nursing staff of Alzheimer's patients in a long-term-care facility

Dental care and oral hygiene are often neglected in nursing homes. This study examines the effect of an education program on the ability of nursing staff to conduct an oral health assessment for a population of persons with Alzheimer's disease and related disorders. The findings of this study showed that the CNA's are as capable as the Licensed Nurses in assessing oral health status. In future training of nursing staff, increased emphasis on identification of problems in specific areas may improve the overall assessments by nurses and nursing assistants.

Extending the limits: minimally invasive surgery

Minimally invasive technology is being applied to an increasing number of surgical procedures. It remains to be seen which techniques will eventually become a 'gold standard' as has the laparoscopic cholecystectomy, and which will fall by the wayside. In the meantime, anesthesiologists must be aware of the unique requirements and complications of laparoscopic surgery.

Immunophenotypic characterization of stromal cells in aspirated human bone marrow samples

The presence of stromal cells was investigated in aspirated bone marrow prepared by the same method as that used for the initiation of human long-term bone marrow culture (hLTBMC). In previous studies, we performed immunocytochemical staining of cytocentrifuge cell preparations using a panel of antibodies with which we characterized stromal cell populations in hLTBMC. This approach allowed morphological as well as immunophenotypic assessment of cells of interest. Morphologically distinctive cell populations expressing vascular cell adhesion molecule-1 and low-affinity nerve growth factor receptor (NGFR) were observed to be present, but no cells expressing alpha-smooth muscle actin were found. Few macrophages were present, consistent with the origin of hLTBMC stroma-adherent macrophages from monocytes and their precursor cells rather than from mature macrophages among the culture-initiating cells. In the absence of double immunostaining, it was not possible to deduce whether CD34+ cells, which were present in varying numbers in the cytocentrifuge preparations, included stromal as well as primitive hematopoietic cells. In addition to single cells, multicellular tissue fragments containing a variety of stromal cell types were detected in many samples. Their presence raises the possibility that at least some components of hLTBMC stroma may arise by explant growth from complex tissue fragments containing vascular and fibroblastic elements. Overall, our results indicate that demonstration of a variety of stroma-associated antigens, in particular NGFR, provides a useful new tool for identifying stromal elements in aspirated bone marrow.

Endoscopic axillary lymph node dissection: an experimental study in human cadavers

BACKGROUND

The role of axillary lymph node dissection in the staging of patients with breast carcinoma is currently under evaluation. As a result of recent advances in minimally invasive techniques, an endoscopic approach to axillary lymph node dissection may be an attractive alternative to lymphadenectomy performed via a standard "open" axillary incision. The purpose of the present study was to evaluate the technical feasibility and safety of such an approach in human cadavers.

STUDY DESIGN

Twelve axillary dissections (right in seven, left in five) were performed in seven cadavers. A 2.5-cm incision was made along the lateral chest wall 12 cm inferior to the apex of the axilla. The subcutaneous axillary space was expanded with a balloon dissector, and exposure was maintained with a prototype external lift device. Endoscopic dissection was performed with three or four 5-mm ports inserted into this space. Histologic analysis was performed to document the number of lymph nodes removed.

RESULTS

The mean dissection time for endoscopic axillary lymphadenectomy was 56.7+/-19 minutes (range, 30-90 minutes). Structures visualized endoscopically included the axillary vein (12 of 12 patients), the long thoracic nerve (12 of 12 patients), the thoracodorsal nerve (10 of 12 patients), and the intercostobrachial nerve (11 of 12 patients). An average of 9.9+/-7.2 lymph nodes (range, 2-22 nodes) was removed from each axilla. Open exploration of the axilla after the endoscopic dissection confirmed no injuries to any neurovascular structures. Residual lymph nodes were removed from the axilla in 7 of 12 dissections (58%; average, 4.2+/-4.0 nodes per specimen).

CONCLUSIONS

These results suggest that endoscopic axillary dissection is feasible with currently available technology. Clinical trials in patients with breast carcinoma may be warranted to evaluate this technique further.