Benjamin R. Lee

A novel method of surgical instruction: international telementoring

Abstract Telemedicine is the use of communication technologies to deliver health care. Telesurgical telementoring represents an advanced form of telemedicine, whereby an experienced surgeon can guide and teach practicing surgeons new operative techniques utilizing current video technology, medical robots, and high-bandwidth telecommunications. This technology can potentially enhance surgeons education, increase patients access to experienced surgeons, and decrease the likelihood of complications due to inexperience with new techniques. A personal computer-based system was developed to immerse a surgical specialist into a distant operating room utilizing public telephone lines. Telesurgical laparoscopic telementoring has successfully been implemented in 27 prior operations between the Johns Hopkins Bayview Medical Center and the Johns Hopkins Hospital, whereby the two institutions were separated by 3.5 miles. We report our experience in performing three successful international surgical telementoring operations, one in Innsbruck, Austria, and two in Bangkok, Thailand.

Laparoscopic visual field Voice vs foot pedal interfaces for control of the AESOP robot

AbstractBackground: In order for robotic devices to be introduced successfully into surgical practice, the development of transparent surgeon/machine interfaces is critical.n Methods: This study evaluated the standard foot pedal for the AESOP robot compared to a voice control interface. Speed, accuracy, learning curves, durability of learning at 2 weeks, and operator-interface failures were analyzed in an ex vivo model.n Results: Foot control was faster and had less operator-interface failures. Voice control was more accurate as measured by ``pass points. The foot control learning curve reached a plateau at the third trial, while the voice control did not fully plateau. Durability of learning favored the foot control but was not significantly different.n Conclusions: Currently, the voice control is more accurate and has the advantage of not requiring the surgeon to look away from the operative field. However, it is slower and may require more attention as an interface. As voice recognition software continues to advance, speed and transparency are anticipated to improve.

Ablation of renal tumors in a rabbit model with interstitial saline-augmented radiofrequency energy: preliminary report of a new technology

OBJECTIVESnTo evaluate the efficacy of interstitial saline radiofrequency energy for reproducibly ablating nonmalignant (control) and malignant (the VX-2 tumor) renal tissue in a rabbit model, and to determine the ability of conventional gray-scale and power sonography to image the tumor and ablative process in real time before, during, and after treatment.nnnMETHODSnThe VX-2 tumor was implanted beneath the renal capsule in 18 rabbit kidneys. Twelve days after implantation, 50 W of 500-kHz radiofrequency energy was delivered into the surgically externalized renal tumor and contralateral control kidney for 30 or 45-second treatment intervals using an interstitial saline-augmented radiofrequency probe (the virtual electrode). Localization of the tumor and response to treatment were imaged with gray-scale and power Doppler ultrasonography. The effect of radiofrequency and extent of the destructive process on benign and malignant renal tissue were evaluated histologically.nnnRESULTSnMean tumor size was 1.3 x 0.7 cm. Both 30 and 45-second treatment intervals provided marked tissue/tumor ablation. Gross anatomic and histologic analysis showed time-dependent ablated lesions averaging 1.4+/-0.3 x 1.0+/-0.3 cm (30-second treatment) and 1.8+/-0.4 x 1.5+/-0.3 cm (45-second treatment), with clear demarcation of the surrounding parenchyma. Conventional gray-scale sonography allowed visualization of the ablative process, and power Doppler ultrasound demonstrated changes in the vascular pattern of the tumor both before and after ablation. No immediate treatment-related complications were observed.nnnCONCLUSIONSnThese preliminary studies in a rabbit model demonstrate the feasibility of using the interstitial saline-augmented electrode to ablate small renal tumors and the ability to simultaneously visualize the ablative process using real-time ultrasonography. This technology may have the potential to treat small renal tumors in a minimally invasive manner in the clinical setting.

Bioimpedance: Novel Use of a Minimally Invasive Technique for Cancer Localization in the Intact Prostate

Prostate cancer is presently diagnosed by transrectal ultrasound (TRUS)‐guided sextant needle biopsy. While echo texture of the tissue can prompt localization of tumor, it is presently imprecise. From 50–75% of men biopsied, based on an abnormal digital rectal examination (DRE) or elevated prostate‐specific antigen (PSA) level, have negative biopsy results. Improvements in tumor localization during TRUS‐guided prostate biopsy are greatly needed. Bioimpedance is an electrical property of biologic tissue. Electric current is limited in living tissue by highly insulating cell membranes; however, different tissue architecture such as cancer may impede current differently and allow detection of differences between normal and abnormal or malignant prostate tissue. Our goal was to assess the utility of bioimpedance measurements in differentiating tumor from normal prostatic tissue in an ex vivo model.

EVALUATION OF SMOOTH MUSCLE AND COLLAGEN SUBTYPES IN NORMAL NEWBORNS AND THOSE WITH BLADDER EXSTROPHY

PURPOSEnMany patients who undergo bladder exstrophy closure as newborns, subsequent epispadias repair and later bladder neck reconstruction become completely continent yet complications can occur. After successful initial exstrophy closure and later epispadias repair some patients may fail to gain sufficient capacity for bladder neck reconstruction or satisfactory capacity and continence after bladder neck reconstruction. In an attempt to understand the pathogenesis of these failures we compared bladder biopsies from normal neonates and those with exstrophy.nnnMATERIALS AND METHODSnBladder biopsies obtained from the midline of the bladder wall just above the base of the trigone from 12 newborns with exstrophy were compared to bladder sections from 9 neonatal cadavers. All bladder specimens were stained with monoclonal antibodies against type I, III or IV collagen and a subset was further stained with Massons trichrome to define the extracellular matrix. All specimens were then analyzed using a color digital image analysis system.nnnRESULTSnAt initial examination of the extracellular matrix there was an increase in the collagen-to-smooth muscle ratio from 0.38 in controls to 1.2 in newborns with exstrophy, comprising an increase in collagen and decrease in smooth muscle. The collagen component of the extracellular matrix was then further defined to quantitate the amount of each collagen type (I, III and IV) deposited. We then evaluated the ratio of collagen type-to-total collagen sampled. Compared to control bladders there was no statistical difference in the amount of type I or IV in the bladders of newborns with exstrophy at initial closure. However, there was a 3-fold increase in type III collagen (0.14 +/- 0.05 to 0.46 +/- 0.2%, p < 0.001) in the bladders of neonatal controls versus newborns with exstrophy.nnnCONCLUSIONSnThis alteration in collagen makeup may represent an earlier developmental stage of the exstrophy bladder at birth, which then remodels and changes after successful initial closure. Further studies are underway to examine the collagen composition of bladders at bladder neck reconstruction, failed closures and augmentation.

Laparoscopic ureteral reimplantation: technique and outcomes.

PURPOSEnWe describe our experience with laparoscopic ureteral reimplantation in 45 adults, and report success rates and complications at intermediate term followup.nnnMATERIALS AND METHODSnWe performed a retrospective chart review of 45 patients who underwent laparoscopic ureteral reimplantation between 1997 and 2007. Demographics, clinicopathological parameters, perioperative course, complications and followup studies were analyzed.nnnRESULTSnElective laparoscopic ureteral reimplantation was performed in 35 female and 10 male patients with a mean followup of 24.1 months (range 1 to 76). All patients presented with distal ureteral stricture with a mean stricture length of 3 cm and a mean +/- SD preoperative serum creatinine of 0.91 +/- 0.04 mg/dl. Mean patient age was 47.8 +/- 2.2 years (range 17 to 87). Mean American Society of Anesthesiologists score was 2 (range 1 to 3). Median estimated blood loss was 150 ml. The overall success rate, defined as radiographic evidence of no residual obstruction, symptoms, renal deterioration or need for subsequent procedures, was 96%. Two patients had recurrent strictures and 1 underwent nephrectomy for flank pain and preexisting chronic pyelonephritis.nnnCONCLUSIONSnAccording to intermediate followup data laparoscopic ureteral reimplantation can be performed with an excellent success rate and low morbidity. Our data substantiate this technique as an effective method for managing distal ureteral stricture.

In vivo measurement of tumor conductiveness with the magnetic bioimpedance method

A noninvasive electromagnetic method has been developed that can effectively measure the in-vivo conductivity difference between rat tumor lines having a low and high metastatic potential. These tumor lines are used in the study of human prostate tumor.

International Surgical Telementoring Using a Robotic Arm: Our Experience

To determine the clinical utility of delivering remote subspecialty surgical care using a novel telesurgical mentoring system with current telemedicine technology. A personal computer-based system ...

Long-Term Follow-Up for Salvage Laparoscopic Pyeloplasty After Failed Open Pyeloplasty

OBJECTIVESnTo report our long-term experience with salvage laparoscopic pyeloplasty after a failed open procedure. Laparoscopic repair of a primary ureteropelvic junction obstruction (UPJO) is associated with very high long-term success. However, there are limited data on patients who have failed previous open pyeloplasty. We have determined that salvage laparoscopic pyeloplasty is an excellent option for these patients.nnnMETHODSnWe queried our laparoscopic pyeloplasty database of 367 patients from July 1994 to May 2007 for patients who had undergone prior open pyeloplasty. We analyzed demographic data, perioperative course, complications, and follow-up studies on identified subjects. We assessed clinical status by verbal pain scale and diagnostic studies. Radiologic follow-up consisted of diuretic renal scan, intravenous pyelography, or both.nnnRESULTSnWe identified 9 patients (2.5%) who underwent salvage laparoscopic pyeloplasty for persistent obstruction after open pyeloplasty. The mean age of our cohort was 30.5 years (range, 19-50 years). Mean operative time was 204 minutes (range, 80-264 minutes), estimated blood loss was 105 mL (range, 20-300 mL), and mean length of stay was 2.1 days (range, 2-3 days). No intraoperative or postoperative complications were reported. All patients reported relief of symptoms in the immediate postoperative period. At a median follow-up of 66 months (range, 12-119 months), 8 of 9 patients (89%) had clinical and radiologic resolution of UPJO with stable renal function, pain free status, and a patent ureteropelvic junction. The remaining patient failed laparoscopic repair within the first year with evidence of persistent obstruction, necessitating endopyelotomy.nnnCONCLUSIONSnOur findings support the use of salvage laparoscopic pyeloplasty as an excellent option for patients who failed previous open pyeloplasty. This approach provides durable long-term outcomes.

Laparoscopic Partial Nephrectomy : an Update on Contemporary Issues

Laparoscopic partial nephrectomy (LPN) is a technically challenging procedure with up to 5-year follow-up data. In this article, incidence of renal cell carcinoma, indications, and contraindications for LPN are presented. In addition, LPN for benign diseases such as atrophic renal segments associated with duplicated collecting systems and calyceal diverticula associated with recurrent UTIs are presented. Hilar clamping, ischemic time, positive margins, and port-site metastasis, in addition to complications and survival outcomes, are discussed. The advantages of lower cost, decreased postoperative pain, and early recovery have to be balanced with prolonged warm ischemia. Its long-term outcomes in terms of renal insufficiency or hemodialysis requirements have not been defined completely. Randomized clinical trials comparing open partial nephrectomy (OPN) versus LPN are needed.