Simon Kimm - Academia.edu (original) (raw)

Papers by Simon Kimm

J Endourol, 2004

To evaluate our experience with the LithoTron lithotripter (Healthtronics, Atlanta, GA), a dry po... more To evaluate our experience with the LithoTron lithotripter (Healthtronics, Atlanta, GA), a dry portable system that utilizes a spark-gap electrode as an energy source. We prospectively evaluated the first 312 treatments performed on 199 men and 99 women with an average age of 43.5 years (range 4 months-80 years), over a 25-month period between May 1999 and June 2001. Of the 468 stones treated, 136 were located in the ureter, 52 in the renal pelvis or ureteropelvic junction, and 230 in the kidney; the sites of 50 were not specified in our database. The average stone size was 8.0 mm (range 1-40 mm). Follow-up included a plain (KUB) film, CT scan, or intravenous urogram (IVU) and was available for 256 patients. "Stone free" was defined as no fragments visible on postoperative images. The mean radiographic follow-up was 74 days (range 0-866 days). Data collection was initially done manually by data sheets, but a Web-based medical database application was developed in order to enter, store, retrieve, and analyze the data more efficiently. The average number of shocks delivered per renal unit was 2689 at 25.8 kV. Seventy-five percent of the procedures were performed with intravenous sedation. Two thirds (169/256) of the patients were rendered stone free with one treatment. According to size, 71% (209/294) of stones <1 cm, 57% (39/68) of stones between 1.0 and 1.5 cm, and 22% (8/36) of stones >1.5 cm were eliminated. There were 23 patients who required further treatment; from the available data, 18 of them are currently stone free. Perioperative complications occurred in 6 patients (2%). No patient had worsening renal function or new-onset hypertension. The effectiveness quotient was 59.3%. The LithoTron lithotripter is satisfactory for stones <1 cm.

World Journal of Urology, 2015

To examine the mode of relapse detection and subsequent treatment after partial or radical nephre... more To examine the mode of relapse detection and subsequent treatment after partial or radical nephrectomy in patients with low-risk (pT1, N0, Nx) kidney cancer. Retrospective study on 1404 patients treated with partial or radical nephrectomy for low-risk kidney cancer from the years 2000-2012. Scans for chest imaging (X-ray or CT) and abdominal imaging (CT, MRI, or ultrasound) are tabulated. For those patients with relapse, the site, mode of detection, and symptoms were recorded. Twenty-one patients relapsed with a median follow-up of 4.1 years for patients who did not relapse. In 17 (81 %) patients, relapse was detected by imaging alone, while 4 (19 %) patients presented with symptoms. Of the patients who relapsed by imaging, 13 (76 %) were treated immediately, while 4 (24 %) continued observation. During the first 3 years of follow-up, 5762 imaging studies were performed to detect 8 relapses, with 6 patients receiving immediate treatment. The median number of imaging studies per patient per year for the first 3 years was 1.7 (interquartile range 1.0, 2.3) including 30 % CT, 3 % MRI, 36 % X-ray, and 31 % ultrasounds. We found a low yield of surveillance imaging in the first 3 years for pT1 kidney cancer. Nearly 1000 imaging studies were performed to detect one relapse that required treatment. Further studies are needed to evaluate the clinical impact of imaging surveillance according to recent guidelines.

Pump Industry Analyst, 2013

The Journal of Urology, 2015

We examined the impact of positive vascular margins in patients with pT3 clear cell renal cell ca... more We examined the impact of positive vascular margins in patients with pT3 clear cell renal cell carcinoma. After excluding patients with non-vascular positive margins, metastasis, lymph node involvement, neoadjuvant therapy, or non-clear cell histology, we identified 224 patients with venous tumor invasion through our institutional database from 1999-2013. Kaplan-Meier analysis and log rank tests were used to evaluate whether positive vascular margins were associated with progression-free survival or cancer-specific survival. Forty-one patients (18%) had a positive vascular margin. Margin status was directly related to the level of invasion (p <0.0001). Compared to the negative vascular margin group, the positive group had significantly worse progression-free survival (p=0.01), but not cancer-specific survival (p=0.3). Similarly, level of vascular thrombus invasion was significantly associated with worse progression-free survival (p=0.02), but not cancer-specific survival (p=0.4). Three-year progression-free survival was worst with inferior vena cava invasion and best with segmental/muscular venous branch invasion (54% [95% CI 34-70] vs. 76% [95% CI 64-85]). Among patients with only main renal vein thrombus, vascular margin status was not associated with progression-free survival (p=0.5) or cancer-specific survival (p=0.2). In patients with pT3N0/XM0 clear cell renal cell carcinoma, positive vascular margins are associated with risk for disease progression. However, the risk of relapse associated with positive vascular margin is driven by extent of vascular thrombus invasion. These findings suggest that the clinical significance of vascular margin status as currently defined in pT3 clear cell renal cell carcinoma is minimal.

PloS one, 2015

The ability to visualize and spare nerves during surgery is critical for avoiding chronic morbidi... more The ability to visualize and spare nerves during surgery is critical for avoiding chronic morbidity, pain, and loss of function. Visualization of such critical anatomic structures is even more challenging during minimal access procedures because the small incisions limit visibility. In this study, we focus on improving imaging of nerves through the use of a new small molecule fluorophore, GE3126, used in conjunction with our dual-mode (color and fluorescence) laparoscopic imaging instrument. GE3126 has higher aqueous solubility, improved pharmacokinetics, and reduced non-specific adipose tissue fluorescence compared to previous myelin-binding fluorophores. Dosing and kinetics were initially optimized in mice. A non-clinical modified Irwin study in rats, performed to assess the potential of GE3126 to induce nervous system injuries, showed the absence of major adverse reactions. Real-time intraoperative imaging was performed in a porcine model. Compared to white light imaging, nerve v...

The Journal of Urology, 2015

Journal of vascular and interventional radiology : JVIR, Jan 10, 2015

To evaluate the feasibility of focal intraluminal irreversible electroporation (IRE) in the urete... more To evaluate the feasibility of focal intraluminal irreversible electroporation (IRE) in the ureter with a novel electrode catheter and to study the treatment effects in response to increasing pulse strength. Five IRE treatment settings were each evaluated twice for the ablation of normal ureter in five Yorkshire pigs (n = 1-4 ablations per animal; total of 10 ablations) with the use of a prototype device under ultrasound and fluoroscopic guidance. Animals received unilateral or bilateral treatment, limited to a maximum of two ablations in any one ureter. Treatment was delivered with increasing pulse strength (from 1,000 V to 3,000 V in increments of 500 V) while keeping the pulse duration (100 μs) and number of pulses (n = 90) constant. Ureter patency was assessed with antegrade ureteropyelography immediately following treatment. Animals were euthanized within 4 hours after treatment, and treated urinary tract was harvested for histopathologic analysis with hematoxylin and eosin and...

Urology, 2006

To report our experience with a novel flexible cystoscopic approach to excise the en block bladde... more To report our experience with a novel flexible cystoscopic approach to excise the en block bladder cuff and juxtavesical ureter during hand-assisted laparoscopic nephroureterectomy. The optimal technique for excising the distal ureter and bladder cuff during nephroureterectomy continues to evolve. Hand-assisted laparoscopic nephroureterectomy was performed in 6 patients. A hand-assist device and two 5 to 12-mm ports were placed in the mid and upper abdomen. Two 10-mm clips were placed on the proximal ureter to occlude it, and the kidney was resected in the usual fashion. An additional 5 to 12-mm port was placed in the midline between the umbilicus and symphysis pubis. The ureter was dissected down into the pelvis to the level of the bladder. Without repositioning the patient, a flexible cystoscope was inserted into the bladder and a 2-cm bladder cuff excised using a 5F electrode on cutting current, with coagulating current used as needed. The specimen was removed intact through the hand port. The mean time to resect the distal bladder cuff was 30 minutes (range 22 to 35). The mean estimated blood loss was 254 mL. The mean operating room time was 264 minutes, mean hospital stay 6.3 days, and mean time to a general diet 2.6 days. All patients underwent cystography at 7 to 10 days postoperatively, with no extravasation or diverticula. Cystoscopic and computed tomography follow-up demonstrated no evidence of recurrence. This technique allows for complete resection of the kidney, distal ureter, and a cuff of bladder, avoiding repositioning.

Urology, 2008

Approximately 5% of all urothelial tumors in adults arise from the upper tracts. While the gold s... more Approximately 5% of all urothelial tumors in adults arise from the upper tracts. While the gold standard treatment is open nephroureterectomy, laparoscopic nephroureterectomy is becoming increasingly popular. Oncologic principles dictate that complete excision of the transmural ureter and bladder cuff and avoidance of urine spillage are paramount. This can be challenging laparoscopically and multiple techniques have been described. We review described surgical techniques, published oncologic data, as well as advantages and disadvantages for each technique including open excision, cystoscopic detachment and ligation, laparoscopic stapling, ureteral intussusception, transurethral resection of ureteral orifice (TURUO) and modifications of TURUO. To date, no controlled studies have been performed demonstrating one technique's superiority.

The Journal of Urology, 2004

Purpose: Urinary tract stones are typically measured using axial images from computerized tomogra... more Purpose: Urinary tract stones are typically measured using axial images from computerized tomography (CT). Such images provide a precise measurement of stone length and width. However, cephalocaudad dimensions can be difficult to determine from axial images. Coronal reconstructions, which can more accurately measure cephalocaudad dimensions, are seldom used to measure stones. We determined if coronal reconstructions could aid in more precisely determining stone size.

The Journal of Urology, 2010

The Journal of Urology, 2010

The Journal of Urology, 2012

The Journal of Urology, 2012

The Journal of Urology, 2012

The Journal of Urology, 2014

Clinical pathways are designed to reduce variability in patient care practices and improve clinic... more Clinical pathways are designed to reduce variability in patient care practices and improve clinical outcomes. We evaluated the effect of implementing a clinical care pathway on length of stay in patients undergoing kidney surgery. After receiving institutional review board approval we evaluated prospective data on consecutive cases of partial and radical nephrectomy performed at our institution from 2000 to 2011. We identified 1,775 partial nephrectomies (1,449 open and 326 minimally invasive) and 1,025 radical nephrectomies (857 open and 168 minimally invasive). We used multivariate linear regression to test for an interaction between procedure type and surgery before vs after the clinical pathway was begun. Median length of stay decreased 40% (from 5 to 3 days) for open surgery and 33% (from 3 to 2 days) for minimally invasive surgery after clinical pathway implementation. Length of stay in patients treated with minimally invasive or open partial nephrectomy and open radical nephrectomy decreased while it remained stable in those who underwent minimally invasive radical nephrectomy. The difference in length of stay between open and minimally invasive partial nephrectomy before and after implementing the clinical pathway decreased by 1.5 days (95% CI 0.56-2.5, p = 0.002). At 30 days postoperatively major complication rates remained similar. The clinical pathway resulted in a significantly shorter length of stay in patients treated with partial and radical nephrectomy without a discernible impact on safety or quality of care. Clinical pathways for kidney surgery should be used and continually optimized to enhance efficiency, patient safety and outcomes.

J Endourol, 2004

To evaluate our experience with the LithoTron lithotripter (Healthtronics, Atlanta, GA), a dry po... more To evaluate our experience with the LithoTron lithotripter (Healthtronics, Atlanta, GA), a dry portable system that utilizes a spark-gap electrode as an energy source. We prospectively evaluated the first 312 treatments performed on 199 men and 99 women with an average age of 43.5 years (range 4 months-80 years), over a 25-month period between May 1999 and June 2001. Of the 468 stones treated, 136 were located in the ureter, 52 in the renal pelvis or ureteropelvic junction, and 230 in the kidney; the sites of 50 were not specified in our database. The average stone size was 8.0 mm (range 1-40 mm). Follow-up included a plain (KUB) film, CT scan, or intravenous urogram (IVU) and was available for 256 patients. "Stone free" was defined as no fragments visible on postoperative images. The mean radiographic follow-up was 74 days (range 0-866 days). Data collection was initially done manually by data sheets, but a Web-based medical database application was developed in order to enter, store, retrieve, and analyze the data more efficiently. The average number of shocks delivered per renal unit was 2689 at 25.8 kV. Seventy-five percent of the procedures were performed with intravenous sedation. Two thirds (169/256) of the patients were rendered stone free with one treatment. According to size, 71% (209/294) of stones <1 cm, 57% (39/68) of stones between 1.0 and 1.5 cm, and 22% (8/36) of stones >1.5 cm were eliminated. There were 23 patients who required further treatment; from the available data, 18 of them are currently stone free. Perioperative complications occurred in 6 patients (2%). No patient had worsening renal function or new-onset hypertension. The effectiveness quotient was 59.3%. The LithoTron lithotripter is satisfactory for stones <1 cm.

World Journal of Urology, 2015

To examine the mode of relapse detection and subsequent treatment after partial or radical nephre... more To examine the mode of relapse detection and subsequent treatment after partial or radical nephrectomy in patients with low-risk (pT1, N0, Nx) kidney cancer. Retrospective study on 1404 patients treated with partial or radical nephrectomy for low-risk kidney cancer from the years 2000-2012. Scans for chest imaging (X-ray or CT) and abdominal imaging (CT, MRI, or ultrasound) are tabulated. For those patients with relapse, the site, mode of detection, and symptoms were recorded. Twenty-one patients relapsed with a median follow-up of 4.1 years for patients who did not relapse. In 17 (81 %) patients, relapse was detected by imaging alone, while 4 (19 %) patients presented with symptoms. Of the patients who relapsed by imaging, 13 (76 %) were treated immediately, while 4 (24 %) continued observation. During the first 3 years of follow-up, 5762 imaging studies were performed to detect 8 relapses, with 6 patients receiving immediate treatment. The median number of imaging studies per patient per year for the first 3 years was 1.7 (interquartile range 1.0, 2.3) including 30 % CT, 3 % MRI, 36 % X-ray, and 31 % ultrasounds. We found a low yield of surveillance imaging in the first 3 years for pT1 kidney cancer. Nearly 1000 imaging studies were performed to detect one relapse that required treatment. Further studies are needed to evaluate the clinical impact of imaging surveillance according to recent guidelines.

Pump Industry Analyst, 2013

The Journal of Urology, 2015

We examined the impact of positive vascular margins in patients with pT3 clear cell renal cell ca... more We examined the impact of positive vascular margins in patients with pT3 clear cell renal cell carcinoma. After excluding patients with non-vascular positive margins, metastasis, lymph node involvement, neoadjuvant therapy, or non-clear cell histology, we identified 224 patients with venous tumor invasion through our institutional database from 1999-2013. Kaplan-Meier analysis and log rank tests were used to evaluate whether positive vascular margins were associated with progression-free survival or cancer-specific survival. Forty-one patients (18%) had a positive vascular margin. Margin status was directly related to the level of invasion (p <0.0001). Compared to the negative vascular margin group, the positive group had significantly worse progression-free survival (p=0.01), but not cancer-specific survival (p=0.3). Similarly, level of vascular thrombus invasion was significantly associated with worse progression-free survival (p=0.02), but not cancer-specific survival (p=0.4). Three-year progression-free survival was worst with inferior vena cava invasion and best with segmental/muscular venous branch invasion (54% [95% CI 34-70] vs. 76% [95% CI 64-85]). Among patients with only main renal vein thrombus, vascular margin status was not associated with progression-free survival (p=0.5) or cancer-specific survival (p=0.2). In patients with pT3N0/XM0 clear cell renal cell carcinoma, positive vascular margins are associated with risk for disease progression. However, the risk of relapse associated with positive vascular margin is driven by extent of vascular thrombus invasion. These findings suggest that the clinical significance of vascular margin status as currently defined in pT3 clear cell renal cell carcinoma is minimal.

PloS one, 2015

The ability to visualize and spare nerves during surgery is critical for avoiding chronic morbidi... more The ability to visualize and spare nerves during surgery is critical for avoiding chronic morbidity, pain, and loss of function. Visualization of such critical anatomic structures is even more challenging during minimal access procedures because the small incisions limit visibility. In this study, we focus on improving imaging of nerves through the use of a new small molecule fluorophore, GE3126, used in conjunction with our dual-mode (color and fluorescence) laparoscopic imaging instrument. GE3126 has higher aqueous solubility, improved pharmacokinetics, and reduced non-specific adipose tissue fluorescence compared to previous myelin-binding fluorophores. Dosing and kinetics were initially optimized in mice. A non-clinical modified Irwin study in rats, performed to assess the potential of GE3126 to induce nervous system injuries, showed the absence of major adverse reactions. Real-time intraoperative imaging was performed in a porcine model. Compared to white light imaging, nerve v...

The Journal of Urology, 2015

Journal of vascular and interventional radiology : JVIR, Jan 10, 2015

To evaluate the feasibility of focal intraluminal irreversible electroporation (IRE) in the urete... more To evaluate the feasibility of focal intraluminal irreversible electroporation (IRE) in the ureter with a novel electrode catheter and to study the treatment effects in response to increasing pulse strength. Five IRE treatment settings were each evaluated twice for the ablation of normal ureter in five Yorkshire pigs (n = 1-4 ablations per animal; total of 10 ablations) with the use of a prototype device under ultrasound and fluoroscopic guidance. Animals received unilateral or bilateral treatment, limited to a maximum of two ablations in any one ureter. Treatment was delivered with increasing pulse strength (from 1,000 V to 3,000 V in increments of 500 V) while keeping the pulse duration (100 μs) and number of pulses (n = 90) constant. Ureter patency was assessed with antegrade ureteropyelography immediately following treatment. Animals were euthanized within 4 hours after treatment, and treated urinary tract was harvested for histopathologic analysis with hematoxylin and eosin and...

Urology, 2006

To report our experience with a novel flexible cystoscopic approach to excise the en block bladde... more To report our experience with a novel flexible cystoscopic approach to excise the en block bladder cuff and juxtavesical ureter during hand-assisted laparoscopic nephroureterectomy. The optimal technique for excising the distal ureter and bladder cuff during nephroureterectomy continues to evolve. Hand-assisted laparoscopic nephroureterectomy was performed in 6 patients. A hand-assist device and two 5 to 12-mm ports were placed in the mid and upper abdomen. Two 10-mm clips were placed on the proximal ureter to occlude it, and the kidney was resected in the usual fashion. An additional 5 to 12-mm port was placed in the midline between the umbilicus and symphysis pubis. The ureter was dissected down into the pelvis to the level of the bladder. Without repositioning the patient, a flexible cystoscope was inserted into the bladder and a 2-cm bladder cuff excised using a 5F electrode on cutting current, with coagulating current used as needed. The specimen was removed intact through the hand port. The mean time to resect the distal bladder cuff was 30 minutes (range 22 to 35). The mean estimated blood loss was 254 mL. The mean operating room time was 264 minutes, mean hospital stay 6.3 days, and mean time to a general diet 2.6 days. All patients underwent cystography at 7 to 10 days postoperatively, with no extravasation or diverticula. Cystoscopic and computed tomography follow-up demonstrated no evidence of recurrence. This technique allows for complete resection of the kidney, distal ureter, and a cuff of bladder, avoiding repositioning.

Urology, 2008

Approximately 5% of all urothelial tumors in adults arise from the upper tracts. While the gold s... more Approximately 5% of all urothelial tumors in adults arise from the upper tracts. While the gold standard treatment is open nephroureterectomy, laparoscopic nephroureterectomy is becoming increasingly popular. Oncologic principles dictate that complete excision of the transmural ureter and bladder cuff and avoidance of urine spillage are paramount. This can be challenging laparoscopically and multiple techniques have been described. We review described surgical techniques, published oncologic data, as well as advantages and disadvantages for each technique including open excision, cystoscopic detachment and ligation, laparoscopic stapling, ureteral intussusception, transurethral resection of ureteral orifice (TURUO) and modifications of TURUO. To date, no controlled studies have been performed demonstrating one technique's superiority.

The Journal of Urology, 2004

Purpose: Urinary tract stones are typically measured using axial images from computerized tomogra... more Purpose: Urinary tract stones are typically measured using axial images from computerized tomography (CT). Such images provide a precise measurement of stone length and width. However, cephalocaudad dimensions can be difficult to determine from axial images. Coronal reconstructions, which can more accurately measure cephalocaudad dimensions, are seldom used to measure stones. We determined if coronal reconstructions could aid in more precisely determining stone size.

The Journal of Urology, 2010

The Journal of Urology, 2010

The Journal of Urology, 2012

The Journal of Urology, 2012

The Journal of Urology, 2012

The Journal of Urology, 2014

Clinical pathways are designed to reduce variability in patient care practices and improve clinic... more Clinical pathways are designed to reduce variability in patient care practices and improve clinical outcomes. We evaluated the effect of implementing a clinical care pathway on length of stay in patients undergoing kidney surgery. After receiving institutional review board approval we evaluated prospective data on consecutive cases of partial and radical nephrectomy performed at our institution from 2000 to 2011. We identified 1,775 partial nephrectomies (1,449 open and 326 minimally invasive) and 1,025 radical nephrectomies (857 open and 168 minimally invasive). We used multivariate linear regression to test for an interaction between procedure type and surgery before vs after the clinical pathway was begun. Median length of stay decreased 40% (from 5 to 3 days) for open surgery and 33% (from 3 to 2 days) for minimally invasive surgery after clinical pathway implementation. Length of stay in patients treated with minimally invasive or open partial nephrectomy and open radical nephrectomy decreased while it remained stable in those who underwent minimally invasive radical nephrectomy. The difference in length of stay between open and minimally invasive partial nephrectomy before and after implementing the clinical pathway decreased by 1.5 days (95% CI 0.56-2.5, p = 0.002). At 30 days postoperatively major complication rates remained similar. The clinical pathway resulted in a significantly shorter length of stay in patients treated with partial and radical nephrectomy without a discernible impact on safety or quality of care. Clinical pathways for kidney surgery should be used and continually optimized to enhance efficiency, patient safety and outcomes.