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Biomedical subjects

A W Partin

Publications and source records attributed to A W Partin.

At least 181 records · Page 10Linked to original sources
PubMed1995

New laparoscopic suturing device: initial clinical experience.

OBJECTIVES: New instrumentation and techniques have enabled laparoscopic surgeons to perform complicated reconstructive procedures. Few centers have attempted these procedures because of the excessive time involved with laparoscopic suturing. The Endo stitch suture device was developed to facilitate suture placement. We clinically compared conventional intracorporeal suturing and Endo Stitch suturing for laparoscopic suture placement and knot tying. METHODS: Intracorporeal suturing was used to complete laparoscopic dismembered pyeloplasties and bladder neck suspensions. Sutures were placed with either needle holders and graspers or the automatic suture device. A total of 85 maneuvers were assessed. Operative videotapes were reviewed to assess accuracy of suture placement, knot tying, and time to place suture and tie knots. All suturing was performed by an experienced laparoscopist. RESULTS: Accuracy of stitch placement and knot tying were equivalent. The average time for stitch placement with the Endo Stitch was 43 +/- 27 seconds (n = 41). This was significantly less than the average stitch placement time for conventional suturing, which was 151 +/- 24 seconds (n = 14). The Endo Stitch knot tying was completed in an average of 74 +/- 50 seconds (n = 17), whereas knot tying with the conventional technique took 197 +/- 70 seconds (n = 13). The needle is automatically loaded in the Endo Stitch after each suture and is immediately ready. CONCLUSIONS: The Endo Stitch device reduced the amount of time needed for placement of stitches and knot tying. Reconstructive laparoscopic procedures requiring multiple suture placement may be completed in a shorter time period using this instrument.

Equipment Design↗
PubMed1995

Can aggressive prostatic carcinomas be identified and can their natural history be altered by treatment?

The factors that determine tumor aggressiveness are multifactorial: age, stage, and grade. Even a well differentiated tumor in a young patient may be aggressive someday because of genetic drift and tumor heterogeneity. In a recent review of 826 favorably selected cases managed with conservative therapy, metastatic disease had developed in 19% with grade I tumors, 42% with grade II, and 74% with grade III at 10 years. Recognizing that < 20% of men present with grade I disease, most prostate cancers are a threat to life in men who are going to live longer than 10 years. On the other hand, some tumors at presentation are too far advanced to cure. To improve the accuracy of preoperative staging in identifying these cases, we have developed nomograms based upon clinical stage, grade, and serum prostate-specific antigen (PSA). Traditionally, patients with high-grade tumors (Gleason 8-10) were never considered candidates for radical prostatectomy because of their poor expectancy for long-term survival. However, with improvements in the staging of prostate cancer and with a reduction in the morbidity of radical prostatectomy, a subset of these patients are potential candidates for curative therapy. We have recently studied the clinical outcome of 72 men with Gleason scores of 8-10 on needle biopsies who presented with clinically localized disease (9 T1c, 22 T2a, 17 T2b, 13 T2c, and 11 T3a). Of the 63 men who underwent radical prostatectomy, 46 (68%) had negative lymph nodes; nine did not undergo surgery because of positive lymph nodes identified from frozen section. The actuarial likelihood of an undetectable serum PSA at 5 years was 43% for men with negative lymph nodes and 45% for men with organ-confined disease. Thus, with proper evaluation, some men with even the most aggressive tumors can be cured by surgery if their pelvic lymph nodes are negative.

Humans↗
PubMed1995

Adhesion formation after transperitoneal nephrectomy: laparoscopic v open approach.

The risk of postoperative adhesion formation is a significant concern with transperitoneal laparoscopic surgery. To evaluate the incidence of adhesions after major interventional urologic laparoscopy, 16 pigs underwent either laparoscopic (N = 8) or transperitoneal open (N = 8) nephrectomy. Adhesions occurred at 12.5% of the operative sites in the laparoscopic group compared with 75% of the operative sites of the open group. Adhesions were present along the incision site in all the pigs in the open group compared with 5 of 40 (12.5%) trocar sites in the laparoscopic group. Adhesion number, grade, and extent were significantly greater in the open group than the laparoscopic group for both nephrectomy and access (incision/trocar) sites (p < 0.05). Transperitoneal laparoscopic urologic surgery in the porcine model results in a marked decrease in adhesion formation compared with incisional transabdominal surgery.

Abdominal Muscles↗
PubMed1995

A quantitative histological evaluation of the dilated ureter of childhood. II: Ectopia, posterior urethral valves and the prune belly syndrome.

A quantitative histological study was performed on specimens of 33 ureters obtained from 14 male and 19 female patients 5 days to 14 years old (mean age 1.2 years). A high resolution color image video analysis system was used to quantify and compare collagen and smooth muscle components of the muscularis layers to normal control ureters from patients of similar ages. In comparing ureters with ectopia (7), ureters with ectopic ureteroceles (20) and control ureters (4) there was not a statistically different collagen-to-smooth muscle ratio among the groups. In the patients with posterior urethral valves the amount of collagen and smooth muscle was not statistically different from controls (p > 0.01), although the collagen-to-smooth muscle ratio was increased. The 4 patients with the prune belly syndrome had a collagen-to-smooth muscle ratio that was markedly elevated (1.21 versus 0.39) compared with controls. When this group was analyzed as 2 separate groups (obstructed versus refluxing ureters) the difference was more apparent (p < 0.004). Ureters with ectopia or ectopic ureteroceles and ureters associated with posterior urethral valves had similar quantitative amounts of smooth muscle (60%, 56% and 52%, respectively). In patients with the prune belly syndrome obstructed ureters had 65% muscle and refluxing ureters had 38% muscle on evaluation. The percentage of collagen was 33% in ureters with ectopia, 37% in those with ureteroceles and 48% in those associated with posterior urethral valves compared with 23% in controls. In the group with the prune belly syndrome there was 30% collagen in obstructed ureters and 62% collagen in refluxing ureters. Our findings demonstrate that while these dilated ureters had different etiologies the overall quantitative composition of collagen-to-smooth muscle ratios was similar except in refluxing ureters associated with the prune belly syndrome. Our study provides further insight into the pathological nature of such ureters and considerations for surgical repair.

Adolescent↗
PubMed1995

Comparison of robotic versus human laparoscopic camera control .

PURPOSE: We investigated the accuracy and use of a robotic surgical arm compared to a human surgical assistant during urological laparoscopic surgery. MATERIALS AND METHODS: A total of 11 patients undergoing pelvic laparoscopic procedures that required identical bilateral surgical manipulations was evaluated. On 1 side a robotic surgical arm was used to manipulate the laparoscopic camera, while on the contralateral side the camera was positioned by a human surgical assistant. The side (left versus right) on which the robot was used was alternated with each case. Parameters assessed included operative time, erroneous camera motions, complications and outcome. RESULTS: All procedures were successfully completed without complications. Laparoscopic camera positioning was significantly steadier with less inadvertent movements when under robotic control (p < 0.0005). Operative times during dissections using the robot or human assistant were not statistically different. CONCLUSIONS: A robotic device can more effectively manipulate and accurately control the video endoscope than a human assistant during laparoscopic procedures.

Female↗
PubMed1995

Complete robot-assisted laparoscopic urologic surgery: a preliminary report.

BACKGROUND: The feasibility and applicability of using surgeon-controlled robotic arms as a substitute for surgical assistants during urologic laparoscopic surgery was assessed. STUDY DESIGN: Seventeen laparoscopic procedures (nephrectomy, n = 4; retroperitoneal lymph node sampling, n = 2; varix ligation, n = 2; pyeloplasty, n = 3; Burch bladder suspension, n = 2; pelvic lymph node dissection, n = 1; orchiopexy, n = 1; ureterolysis, n = 1; and nephropexy, n = 1) were performed by a single laparoscopic surgeon assisted by one or two robotic arms directly controlled by the operating surgeon. One robotic arm controlled the laparoscope and was maneuvered by a foot pedal. The second robotic arm served as a retractor and was manipulated by a hand control. Assessment of robotic positioning, laparoscopic instrument port placement, time for setup and breakdown of the operative field, operative time, outcome, and operative complications were made for each procedure and compared with historical human-assisted laparoscopic procedures. RESULTS: Standard laparoscopic port placement was adequate for use of the robotic arms. All procedures were successfully completed with three minor surgical complications not related to the use of the robotic arm. Robotic arm positioning on the operating room table differed for each type of procedure, yet placement of the robotic arm controlling the laparoscope on the surgeon's side provided optimal surgical views. In three cases, intraoperative bleeding required human assistance for camera control. There was no increase in operating time when the robotic arms were used. There was no difference between the setup and breakdown time for this series of complete robot-assisted procedures when compared with either a nonrobot-assisted series (p > 0.05) or another robotic series completed prior to initiation of this study when no focus was made on setup and breakdown times and in which the robotic arm and human surgical assistant were compared (p < 0.05). CONCLUSIONS: We found that simultaneous use of remote controlled robotic arms as surgical assistants is feasible in genitourinary laparoscopic surgery. The potential long-term cost effectiveness of using robotic surgical assistants in laparoscopic surgery highlights the economic impact of this research and warrants further investigation.

Adult↗
PubMed1995

Deoxyribonucleic acid ploidy analysis as a predictor of recurrence following radical prostatectomy for stage T2 disease.

Deoxyribonucleic acid (DNA) ploidy image analysis was used postoperatively to predict recurrence of 112 clinically localized adenocarcinomas of the prostate. All men underwent radical retropubic prostatectomy between 1978 and 1991. Patients with positive lymph nodes or positive seminal vesicles were excluded because progression is nearly inevitable in these men. The minimum followup for men without progression was 5 years (range 5 to 15). Patients were considered to have clinically evident disease progression based on local recurrence (8%), distant metastases (4%) and/or an isolated elevation of serum prostate specific antigen (87%). Of the tumors 43% were diploid and 57% were nondiploid. In a multivariate analysis comparing grade, ploidy, capsular penetration and surgical margins, Gleason sum was the best predictor of progression (p < 0.0001). Nevertheless, a subset of patients remained with well to moderately differentiated Gleason grade tumors (Gleason sum 6 or less) who failed. DNA ploidy was able to predict recurrence in this particular group (p = 0.034). In addition, we compared different methods of tissue preparation to determine which best predicted progression. We found that ploidy analysis on tissue sections was more predictive than ploidy performed on disaggregated tissue. In summary, our study revealed that DNA ploidy analysis can offer additional prognostic information following radical prostatectomy for men with low grade prostatic adenocarcinoma.

Actuarial Analysis↗
PubMed1994

Nuclear shape analysis for the assessment of local invasion and metastases in clinically localized prostate carcinoma.

BACKGROUND: Nuclear shape analysis of histologic sections from radical prostatectomy specimens has retrospectively predicted outcome in patients with clinically localized prostate carcinoma. If outcome could be predicted preoperatively by nuclear shape analysis, patients might be selected better for definitive surgical therapy. Morphometric analysis of preoperative biopsies, however, has not correlated positively with values obtained from analysis of prostatectomy specimens. METHODS: The nuclear shapes of histologic specimens of 20 organ-confined carcinomas, 10 periprostatic fat-invasive carcinomas, 10 seminal vesicle-invasive carcinomas, and 12 lymph node-metastatic carcinomas from 52 patients who had undergone radical prostatectomy for clinically localized disease were evaluated. RESULTS: Nuclei from areas of extraprostatic invasion or regional lymph node metastases were less round than those from the corresponding intraprostatic portion of the tumor (nuclear roundness factor (mean +/- SD) PPF, 51.2 +/- 3.1 vs. 31.2 +/- 3.2; SV, 52.4 +/- 4.1 vs. 31.6 +/- 2.5; and LN, 57.3 +/- 3.1 vs. 36.4 +/- 1.8; paired Student's t tests, P < 0.001). Cells sampled from the periphery of organ-confined tumors had a greater nuclear roundness factor (49.1 +/- 1.5) than did those sampled from the center (34.5 +/- 2.0; P < 0.001) or randomly throughout the tumor (37.8 +/- 1.6; P < 0.001). Nuclear roundness factors for all extraprostatic tumor foci and for peripheral tumor cells in organ-confined disease were similar (analysis of variance, P > 0.05). The intraprostatic portions of randomly sampled primary tumors had similar nuclear roundness factors, regardless of pathologic stage (P > 0.05). Among organ-confined carcinomas, nuclear shape was unrelated to tumor volume. CONCLUSIONS: Pathologic stage in clinically localized prostate carcinoma cannot be determined by the nuclear shape profiles of intraprostatic tumor cells. Thus, patients with a poor prognosis or high pathologic stage can be recognized only when samples for morphometric analysis include high proportions of nuclei from the extra-prostatic carcinoma and nuclei from the periphery of organ-confined carcinoma that may not be sampled routinely by prostate biopsy.

Adipose Tissue↗
PubMed1994

Molecular and cellular changes associated with the acquisition of metastatic ability by prostatic cancer cells.

Presently, one of every four cancers diagnosed in American males is of prostatic origin. Once prostatic cancer metastasizes, it is a fatal disease for which no therapy presently available is curative. Because of these facts, there is a growing interest in the early detection and screening of men for prostate cancer. Such screening could potentially identify 10 million American men with histological prostatic cancer. It is estimated that approximately 7% (700,000) of these men will eventually die from their disease if left untreated. This raises the critical question of which of the remaining 93% (9,300,000) of men with nonlethal, but potentially life-altering, histologically detectable prostatic cancer should receive therapy. There is no diagnostic method presently available which allows men with histologically detectable prostatic cancer, who require immediate therapy, to be distinguished from those requiring either delayed therapy or no treatment. Acquisition of metastatic ability by such histologically detectable prostatic cancer cells is a definitive criterion upon which to base such a diagnostic substaging method. Identification of the cellular and molecular requirements for acquisition of metastatic ability by prostatic cancer cells is needed for the development of such methods. This article will focus on what is known concerning general cellular and specific molecular changes associated with the acquisition of metastatic ability by prostatic cancer cells, and suggested areas for future studies.

Biomarkers, Tumor↗
PubMed1994

Prediction of disease-free survival after therapy in Wilms' tumor using nuclear morphometric techniques.

The outlook for children with Wilms' tumor has markedly improved with the use of multimodal therapy, and survival currently exceed 85%. Current trends have been to use less intense therapy for children whose tumors have favorable histology (FH). By decreasing the amount of therapy given to patients whose conditions have an excellent chance of responding, the need for accurate criteria to separate high-risk and low-risk groups becomes imperative. Nuclear morphometric techniques have been developed and extensively tested in the author's laboratory. Preliminary studies of FH Wilms' tumors demonstrated the applicability of this technique. Herein, the authors present a retrospective study of 108 patients with FH tumors, with a mean follow-up period of 1,994 +/- 107 days (66 months) for those whose tumors did respond to therapy, and 686 +/- 61 days (23 months) for those whose tumors did not respond. The univariate predictors were age (P = .02), the skewness of nuclear roundness factor (SNRF) (P = .009), and the mean of the lower five values for nuclear ellipticity, measured by the feret diameter method (L5EFD) (P = .01). A multivariate analysis combining all three variables better separated the two groups (P = .00016). A probability function curve was constructed to predict poor prognosis. Kaplan-Meier actuarial survival analysis was used to predict disease-free survival as clinical progression, and separated the two groups (P = .0004, Wilcoxon-Gehan statistic). These results suggest that nuclear morphometry is useful in the initial assessment of patients with Wilms' tumor.

Adolescent↗
PubMed1994

Evaluation of serum prostate-specific antigen velocity after radical prostatectomy to distinguish local recurrence from distant metastases.

OBJECTIVE: Serum prostate-specific antigen (PSA) values are most useful for prediction of disease recurrence after surgery. It is unknown whether a detectable PSA level after surgery indicates a local recurrence potentially benefiting from pelvic irradiation or distant metastases requiring hormonal treatment. METHODS: We analyzed postoperative rate of change of serum PSA levels as a predictor of local versus distant disease recurrence after radical prostatectomy. Between 1982 and 1991, 1,058 men underwent radical prostatectomy for localized prostate cancer and follow-up consisted of determining serum PSA levels and digital rectal examinations. Clinical follow-up of 542 men for four or more years and 78 men for eight or more years yielded ten-year actuarial disease recurrence rates of 4 percent for local recurrence, 8 percent for distant metastases, and 23 percent for an isolated elevation of serum PSA level only. Fifty-one patients with isolated elevations of PSA levels only were followed expectantly until they were diagnosed with either local or distant metastases. RESULTS: A linear mixed effects regression analysis was used to model these data. Using these models, the time to a serum PSA level of 0.5 ng/mL, the PSA level one year following surgery, pathologic stage, Gleason sum, and the rate of change of PSA (PSA velocity [PSAV]) were tested as predictors of local versus distant metastases. A combination of PSAV, pathologic stage, and Gleason grade best distinguished local from distant metastases. CONCLUSIONS: These data suggest that PSAV in men with an isolated elevation of PSA levels following radical prostatectomy might aid in clinical decision making.

Actuarial Analysis↗
PubMed1994

Benign and malignant prostatic neoplasms: human studies.

Because the present ability to treat and cure patients with prostate cancer is limited to those patients with pathologically organ-confined disease, it has become increasingly important to diagnose this disease at an early stage, when cure is most likely. Recent advances in imaging may allow the urologist and the pathologist to make the diagnosis of prostate cancer much earlier in the natural course of the disease. It therefore becomes imperative to have methods available to predict which patients have a high probability of progressing so that treatment can be assigned logically and appropriately. Our current methods of prognosis determination (stage and grade) do not allow accurate assessment of tumor behavior in the majority of individual patients with prostate cancer. Therefore, more accurate quantification of nuclear and cellular changes that take place as a tumor progresses to take on the aggressive (metastatic) phenotype are urgently needed. Experimental techniques have proven useful in answering these questions and now seem ready for large-scale testing in clinical studies.

Aging↗
PubMed1994

Cancer control and quality of life following anatomical radical retropubic prostatectomy: results at 10 years.

The experience after 10 years with anatomical radical retropubic prostatectomy at The Johns Hopkins Hospital is reviewed. Between April 1982 and March 1991, 955 men with clinically localized prostate cancer (clinical stages T1 to T2) underwent staging pelvic lymphadenectomy and anatomical radical retropubic prostatectomy. Using actuarial analysis, at 10 years the likelihood of an undetectable prostate specific antigen (PSA) level was 70%, isolated elevation of PSA 23%, distant metastases 7% and local recurrence 4%. The actuarial likelihood of an elevated serum PSA increased with increasing pathological stage: the 10-year likelihood of freedom from PSA relapse was 85% for men with organ confined disease, 82% with focal capsular penetration, 54% with established capsular penetration and Gleason score 2 to 6 disease, 42% with established capsular penetration and Gleason score 7 to 10 disease, and 43% with seminal vesicle involvement. These data indicate that radical prostatectomy cures the majority of men with organ confined disease or with well to moderately well differentiated tumors that have penetrated the prostatic capsule to the extent where it is possible to obtain a clear surgical margin. Radical prostatectomy should be reserved for patients who can be cured and who will live long enough to benefit from it. These are also the patients who have the best quality of life postoperatively.

Actuarial Analysis↗
PubMed1994

The clinical usefulness of prostate specific antigen: update 1994.

In conclusion, PSA is the first prostate specific serum marker of clinical usefulness in urology. It represents a valuable clinical tool that has improved our ability to detect early prostate cancer and to monitor response to therapy. While large PSA screening studies have demonstrated an appreciable increase in the detection of organ confined, potentially curable prostate cancers, no study to date has yet demonstrated that the increased detection rate will decrease the prostate cancer-specific mortality rate. Yet more importantly, no study to date has demonstrated that early diagnosis using PSA will not decrease the prostate cancer specific mortality rate and until such data exist, PSA should be used to aid in early diagnosis and treatment planning for men with prostate cancer. PSA, when combined with other variables such as Gleason score and clinical stage, improves the prediction of pathological stage for prostate cancer. The introduction of PSA velocity and age specific reference ranges should further enhance the clinical usefulness of PSA. New advances in PSA research hold great promise for further improvements in PSA, and truly make it the most important and useful tumor marker for adenocarcinoma of the prostate.

Adenocarcinoma↗
PubMed1994

Radical prostatectomy for high grade disease: a reevaluation 1994.

Traditionally, patients with high grade tumors (Gleason score 8 to 10) were not considered candidates for radical prostatectomy because of poor long-term survival rate. However, with improvements in the staging of prostate cancer and a reduction in the morbidity of radical prostatectomy, it is reasonable to reevaluate the results of radical prostatectomy in high grade disease in a contemporary setting. We studied the clinical outcome of 72 men with Gleason scores 8 to 10 on needle biopsy who presented with clinically localized disease (T1c [9], T2a [22], T2b [17], T2c [13] and T3a [11]). Nine patients (13%) did not undergo radical prostatectomy because of positive lymph nodes identified on frozen section. Of the 63 men who underwent radical prostatectomy 43 (68%) had negative lymph nodes and 20 (32%) had positive lymph nodes. The actuarial likelihood of having an undetectable serum prostate specific antigen at 5 years was 43% for men with negative lymph nodes and 45% for men with specimen confined disease. In 7 men (9%) distant metastases developed and all had positive lymph nodes at surgery. These data suggest that men with high grade disease who are suitable candidates for radical prostatectomy should have the pelvic lymph nodes evaluated. If the lymph nodes are negative, the patient may benefit from an attempt at surgical cure.

Actuarial Analysis↗
PubMed1994

Small high grade adenocarcinoma of the prostate in radical prostatectomy specimens performed for nonpalpable disease: pathogenetic and clinical implications.

It has been suggested that poorly differentiated areas in prostatic carcinoma evolve from more well differentiated cancer with time and increasing tumor volume. However, the association of high grade tumor with increasing tumor volume may merely reflect a growth advantage of the high grade tumor, whereby most high grade tumors would be large by the time they were clinically detected. Prior reports analyzing the relationship of tumor volume and grade suffer from studying fairly advanced tumors in which the relationship of tumor volume and grade at inception of prostate cancer could not be addressed. We evaluated 720 individual tumor foci in 153 radical prostatectomy specimens removed for early prostate cancer detected by screening techniques. Although tumor volume was related to grade, the correlation was weak (r = 0.254). Of 13 peripherally located high grade tumors (Gleason score 8 to 10) 6 (46%) were less than 1 cc. Of 106 peripheral tumors with some Gleason pattern 4 or 5 component 48 (45%) were less than 1 cc. These small high grade tumors were frequently associated with high grade prostatic intraepithelial neoplasia. Small high grade cancers were uncommon within the transition zone, where there exists a greater tendency for large low grade cancers to arise. In this radical prostatectomy series of nonpalpable prostate cancer 9% of the prostates contained tumor foci that were predominantly Gleason pattern 4 or 5 and that measured 1 cc or less. Based on these findings, if some patients with low to intermediate grade cancer are to be followed expectantly, they should undergo widespread sampling of the prostate to enhance the detection of multifocal small high grade disease. The finding of a large proportion of low volume, high grade carcinoma reveals that prostate cancer has the potential to be high grade early in its course and need not arise from low grade carcinoma that has evolved with time and volume.

Adenocarcinoma↗
PubMed1994

Telerobotic assisted laparoscopic surgery: initial laboratory and clinical experience.

OBJECTIVES: To assess the feasibility of telerobotic assisted surgery. METHODS: In a laboratory model, a cholecystectomy, splenectomy, and nephrectomy were performed by an inexperienced surgeon who was being mentored by an experienced surgeon stationed at a remote site. The remote surgeon controlled the laparoscopic camera by utilizing a telerobotic system. In patients, laparoscopic cholecystectomy, varix ligation, and bladder suspension were performed by an experienced team utilizing a robotic system controlled by an experienced surgeon from a remote site. RESULTS: In both the laboratory and clinical setting, all procedures were successfully completed without complications. CONCLUSIONS: Current technology is available to successfully allow for telerobotic assisted surgery.

Animals↗