Biomedical subjects

Lincoln J Maynes

Publications and source records attributed to Lincoln J Maynes.

6 recordsLinked to original sources

PubMed2006

A novel single step percutaneous access sheath: the initial human experience.

PURPOSE: A novel 1-step percutaneous access sheath NS has been developed that allows the insertion of a dilating balloon and renal access sheath in a single step. We present the initial human experience with this sheath. MATERIALS AND METHODS: We performed a retrospective chart and database review of the initial 30 consecutive patients undergoing percutaneous nephrostolithotomy using the NS. Data collected included patient demographics, operative and recovery parameters, and complications. RESULTS: Mean patient age was 50.4 years (range 11 to 81), mean body mass index was 31.63 kg/m(2) (range 17.1 to 65) and mean preoperative stone area was 6.23 cm(2) (range 1 to 14.6). Six and 3 patients had full and partial staghorn calculi, respectively. Access was achieved via the upper pole in 16 patients, middle pole in 7 and lower pole in 7. Mean operative time was 114.8 minutes (range 61 to 237). Mean estimated blood loss was 145.5 cc (range 10 to 500) and mean postoperative hospital stay was 4.89 days (range 2 to 14). A total of 23 patients (76.7%) had no residual calculi on postoperative computerized tomography, 5 (16.7%) had residual fragments 4 mm or less and 2 (6.7%) had residual stone fragments greater than 4 mm. There were no complications related to the NS. CONCLUSIONS: The NS is safe, easy to use and has potential advantages compared to currently available renal access sheaths.

Adolescent↗

PubMed2005

Control of the renal artery and vein with the nonabsorbable polymer ligating clip in hand-assisted laparoscopic donor nephrectomy.

BACKGROUND: The large and variable size of the renal vein has prompted most surgeons to select linear stapling devices to secure the vein during laparoscopic donor nephrectomy. Although effective, these stapling devices have a potential for misfire. Use of the nonabsorbable polymer ligating (NPL) clip during laparoscopic donor nephrectomy provides increased graft vessel length compared with the stapling device, and the NPL clip has a locking mechanism which may increase security compared with standard titanium clips. The objective of this study was to evaluate the safety and efficacy of the NPL clip for control of the renal artery and vein during hand-assisted laparoscopic donor nephrectomy (HALDN). METHODS: A retrospective chart review of 50 consecutive HALDN patients was conducted where two parallel NPL clips were used to control both the renal artery and vein. Information collected included demographic data, operative and postoperative data, and complications. RESULTS: Mean donor age was 33.4 years and body mass index was 25.8 kg/m2. Mean operative time was 266.0 min, mean hospital stay was 3.2 days, and mean warm ischemia time was 123.3 seconds. There were no transfusions, open conversions, or complications related to use of the NPL clip. A US 16,300 dollars disposable cost savings was seen during this 1-year period alone. CONCLUSIONS: The NPL clip was 100% safe and effective in controlling the renal artery and vein during HALDN, allowed for additional vessel length, and resulted in a disposable cost savings of US 362 dollars per patient.

Adult↗

PubMed2005

Simplified technique for laparoscopic extravesical ureteral reimplantation in the porcine model.

BACKGROUND AND PURPOSE: Laparoscopic intravesical and standard Lich-Gregoir repair have been reported but are technically challenging. Herein, we present our experience with a simplified laparoscopic reimplantation of the ureter to correct vesicoureteral reflux (VUR). MATERIALS AND METHODS: Bilateral VUR was created cystoscopically in six minipigs, as confirmed by a static cystogram 6 weeks later. The laparoscopic extravesical correction of VUR was performed utilizing a full-thickness cystotomy. The ureter was transposed inside the bladder, and a full-thickness bladder closure was performed. No attempt was made to cover the ureter with urothelium. No stents or catheters were utilized postoperatively. Three months after reimplantation, the animals were evaluated with serology, a static cystogram, an intravenous urogram (IVU), and gross pathologic and histopathologic examination. RESULTS: The postoperative cystograms confirmed no reflux in all the reimplanted ureters and residual grade 1 to 3 reflux in the non-reimplanted ureters. All pigs voided normally and were completely continent. Cystoscopic evaluation revealed complete epithelialization over the reimplanted ureter. One surgical complication occurred: the ureter was incorporated into the bladder closure and became obstructed. The IVU in all other pigs demonstrated patent ureters with prompt function. CONCLUSIONS: Laparoscopic reimplantation of the ureter utilizing this modified Lich-Gregoir approach corrected reflux in all animals. The full-thickness bladder incision and intravesical transposition of the ureter greatly simplifies the laparoscopic procedure. This laboratory experience encourages further clinical evaluation in the pediatric population with VUR.

Animals↗

PubMed2005

Hand-assisted laparoscopic partial nephrectomy in the porcine model using gelatin matrix hemostatic sealant without hilar occlusion.

BACKGROUND AND PURPOSE: Gelatin matrix hemostatic sealant (GMHS) has been used for hemostasis during partial nephrectomy with hilar clamping. The objective of this study was to determine the ability of GMHS to achieve hemostasis without hilar clamping in the porcine model. MATERIALS AND METHODS: In this feasibility study, eight farm pigs underwent a left-hand-assisted laparoscopic partial nephrectomy (HALPN). The lower fourth of the kidney was removed with cold scissors, and GMHS was applied laparoscopically. Samples were collected for measurement of serum hemoglobin (Hb) and creatinine (Cr) prior to surgery and at 4 and 30 days after HALPN. The kidneys were harvested at 30 days, and retrograde pyelograms and pathologic analysis were performed. RESULTS: Application of GMHS achieved complete hemostasis in all eight animals. The mean estimated blood loss was 40 mL, and the operating time was short (mean 92.5 minutes). In three kidneys, a significant collecting system opening was noted but not repaired. At harvest, there were no hematomas, infections, or urine leaks in any animals. In one animal, a 2-cm contained fluid collection was identified. There was no difference in the preoperative and harvest Hb (9.63 v 9.21 g/dL; P = 0.49), but there was a slight increase in Cr (1.21 v 1.46 mg/dL; P = 0.01) possibly because of the decreased renal mass after partial nephrectomy. CONCLUSION: Even without hilar occlusion, GMHS was 100% safe and effective in controlling bleeding after HALPN in the porcine model. Avoidance of hilar occlusion may reduce the risk associated with warm renal ischemia and the extra dissection required to isolate the hilum in preparation for clamping.

Animals↗

PubMed2005

Comparison of nonabsorbable polymer ligating and standard titanium clips with and without a vascular cuff.

PURPOSE: To compare the efficacy of nonabsorbable polymer ligating (NPL) and titanium clips applied with and without a 1-mm vascular cuff at physiologic and supraphysiologic pressures. MATERIALS AND METHODS: An in vitro equine-vessel model was created to test clip occlusion strength. Ten-millimeter NPL and standard Ti clips were applied to veins (10 mm) and arteries (10, 6, and 5 mm) with and without a 1-mm cuff and tested until they held a pressure of 300 mm Hg (veins) or 760 mm Hg (arteries) for 2 minutes or leaked. RESULTS: The NPL clip was statistically more secure on 10-mm veins with and without a cuff, 10-mm arteries with and without a cuff, and 6-mm arteries with a cuff than was the Ti clip. Leaving a 1-mm cuff resulted in a statistically higher leak point in all vessels tested except the 6-mm arteries secured with the Ti clip. CONCLUSIONS: The NPL clip was more secure than the Ti clip on larger arteries and veins. A 1-mm vascular cuff enhances the security of both NPL and Ti clips in vessels of all sizes. The NPL clip is secure and reliable in securing both arteries and veins.

Animals↗

PubMed2004

Laparoscopic warm renal ischemia in the solitary porcine kidney model.

OBJECTIVES: To determine the effect of a laparoscopic approach on warm renal ischemia in the pig with a solitary kidney. Although the maximal safe duration for warm ischemia during open partial nephrectomy is commonly accepted to be 30 minutes, the maximal safe ischemic time during laparoscopic partial nephrectomy has not been previously determined. METHODS: Sixteen farm pigs underwent unilateral laparoscopic right nephrectomy. Two weeks later, the pigs underwent complete laparoscopic mobilization of the remaining left kidney and were randomized to complete hilar clamp times of 0, 30, 60, or 90 minutes. Serum creatinine was evaluated before right nephrectomy and at days 0, 2, 4, 7, 14, and 30 after renal ischemia during laparoscopy. All renal specimens were evaluated by an experienced nephropathologist in a blinded fashion. RESULTS: The serum creatinine remained stable at all points in the control and 30-minute ischemia groups. The serum creatinine level rose initially on days 2 and 4 in the 60-minute and 90-minute ischemia groups but returned to baseline by day 7. At harvest, no statistically significant difference was found among the groups in serum creatinine or histologic features. CONCLUSIONS: Renal ischemic times up to 90 minutes during laparoscopy were well tolerated by the solitary porcine kidney. Possible explanations for this finding include the protective effect of a solitary kidney and the potential protective effect of relative ischemic preconditioning provided by the pneumoperitoneum.

Animals↗