The Da Vinci Single-Port (SP) Treatment of Nutcracker Syndrome: A Case Report of a Novel Approach.

Nutcracker syndrome (NCS) is a rare disease affecting the left kidney. Surgical management is the only choice of treatment. Minimal invasive surgeries can be effective and may prevent complications of the major surgery. We present the case of a 33-year-old woman suffering from chronic left flank pain, diagnosed with NCS and treated with extravascular stents. Robotic-assisted extravascular stent insertion was performed using the Da Vinci single-port (SP) (Intuitive Surgical, Inc., Sunnyvale, USA) system. This approach offers the advantages of minimal invasiveness, precise stent placement, and reduced operative time. To our knowledge, this is the first case of using Da Vinci SP for this indication. Further studies are needed to evaluate the long-term outcomes and safety.

Patient-Reported Outcomes for Robot-Assisted Laparoscopic Extravascular Renal Vein Stent Placements for Nutcracker Syndrome.

Introduction: Nutcracker phenomenon is the compression of the left renal vein between the superior mesenteric artery (SMA) and the abdominal aorta. Nutcracker syndrome refers to the presence of nutcracker phenomenon with symptoms. Between 2016 and 2022, we performed 18 robot-assisted laparoscopic extravascular renal vein stent (RALERVS) placements. We sought to assess patient-reported outcomes of RALERVS placement by a single institution. Methods: We performed a single-center retrospective review of 18 patients with a minimum of 3 months follow-up. Symptoms were assessed utilizing a questionnaire conducted with a 5-point Likert scale at a minimum of 3 months postoperatively. Five on the Likert scale was severe while 1 was none. Primary study outcomes compared pre- and postoperative patient-reported symptom scores. Results: Twelve out of 18 patients responded to the survey. The average length of time from date of operation to completion of survey was 2.6 years. Average age of the cohort was 36 years with a mean BMI of 19.4 kg/m2. There was only one man. Mean operative time was 137 minutes and mean estimated blood loss was 12 mL. Mean preoperative SMA angle was 19° and mean postoperative SMA angle was 36°. Patients reported that flank pain, abdominal pain, nausea, headaches, back pain, pelvic pain, and early satiety improved (p < 0.05). Ten of 12 respondents would recommend RALERVS for nutcracker syndrome. Conclusion: RALERVS demonstrates an effective treatment for nutcracker syndrome. Patients reported improved symptoms at 3 months postoperatively across multiple domains. Further studies need to be conducted to assess long-term durability of the extravascular renal vein graft.

Robot-assisted extravascular stent for nutcracker syndrome: A case report.

Nutcracker syndrome (NCS) is a rare condition caused by compression of the left renal vein (LRV) between the aorta and superior mesenteric artery. Surgical treatment is reserved for patients with severe symptoms and failure of conservative treatment. A 31-year-old woman diagnosed in adolescence with NCS has had recurrent pain since age 15. For 30 days, she has had severe left flank pain and microhematuria. The patient underwent extravascular stent placement around the LRV with the Da Vinci Xi. In 30 months of follow-up, the patient has no pain and the LRV remained without compressions or thrombosis.

Laparoscopic placement of left renal vein extravascular stenting in treatment of nutcracker syndrome: Techniques and long-term outcomes.

OBJECTIVES: We aimed to assess the feasibility and efficacy of laparoscopic extravascular stent in treatment of nutcracker syndrome by transperitoneal or retroperitoneal approach. METHODS: Seventy-six patients with nutcracker syndrome were retrospectively enrolled from a tertiary referral center, and underwent transperitoneal (63 patients) or retroperitoneal (13 patients) laparoscopic extravascular stent from March 2011 to December 2020. Surgical parameters, complications, imaging and clinical outcomes were collected and analyzed. RESULTS: All procedures were successfully carried out without open conversion. The median operation time, estimated blood loss, and postoperative hospital day were 120 (interquartile range [IQR]: 90-144) min, 20 (IQR: 10-30) ml, and 7 (IQR: 6-9) days. At a median follow-up of 52 (range: 9-127) months, 60 (79%) patients had complete symptom resolution, 14 (18%) patients had significant symptom improvement, and 2 (3%) patients reported no symptom improvement. Ninety-four percent (50/53) of hematuria, 91% (30/33) of proteinuria, and 89% (25/28) of flank/abdominal pain resolved after extravascular LRV stenting. No significant differences were detected in surgery parameters and recovery rates of clinical symptoms between two approaches (each p > 0.05). However, patients with transperitoneal approach need longer to achieve complete recovery compared with retroperitoneal approach (8.7 vs. 1.5 months, p = 0.016). CONCLUSIONS: Laparoscopic extravascular stent performed either transperitoneally or retroperitoneally is a feasible and effective option in treatment of nutcracker syndrome. Retroperitoneal laparoscopic extravascular stent required shorter time to achieve complete recovery, which should be considered whenever possible in surgical decision-making.

New strategy of using double-network hydrogel extravascular stent for preventing venous graft restenosis after coronary artery bypass grafting.

OBJECTIVE: Effective therapies for the prevention of vein graft failure, which frequently occurs in coronary artery bypass grafting (CABG) due to intimal hyperplasia (IH), are still lacking. Here, we investigated the effects of the perivenous application of double-network hydrogel on vein grafts in carotid artery bypass grafting in a rabbit model. METHODS: Healthy New Zealand white rabbits were randomized into the following groups: no graft, graft, or graft + Double-network hydrogel external stent (DNHES). The rabbits' carotid artery was bypassed via the jugular vein. Double-network hydrogel external stent was wrapped around the jugular graft after the anastomoses were completed. Blood flow parameters and tissue histology of the vein grafts were evaluated. RESULTS: Compared with the untreated vein grafts at 12 weeks after the surgery, the DNHES significantly improved graft flow, attenuated intimal and medial thickening, reduced the anti-proliferating cell nuclear antigen proliferation index of the vein grafts, decreased the mRNA and protein expression of Mitogen-Activated Protein Kinase (MAPK) and Transforming Growth Factor-ß (TGF-ß), and increased the mRNA and protein expression of endothelial Nitric Oxide Synthase (eNOS). CONCLUSION: The perivenous application of DNHES exerts beneficial effects on vein grafts, reduces the inflammatory response in carotid artery bypass grafting in a rabbit model, and appears to be a safe and promising strategy to prevent vein graft failure.

A novel Nanocellulose-Gelatin-AS-IV external stent resists EndMT by activating autophagy to prevent restenosis of grafts.

Vein grafts are widely used for coronary artery bypass grafting and hemodialysis access, but restenosis remains the "Achilles' heel" of these treatments. An extravascular stent is one wrapped around the vein graft and provides mechanical strength; it can buffer high arterial pressure and secondary vascular dilation of the vein to prevent restenosis. In this study, we developed a novel Nanocellulose-gelatin hydrogel, loaded with the drug Astragaloside IV (AS-IV) as an extravascular scaffold to investigate its ability to reduce restenosis. We found that the excellent physical and chemical properties of the drug AS-IV loaded Nanocellulose-gelatin hydrogel external stent limit graft vein expansion and make the stent biocompatible. We also found it can prevent restenosis by resisting endothelial-to-mesenchymal transition (EndMT) in vitro. It does so by activating autophagy, and AS-IV can enhance this effect both in vivo and in vitro. This study has added to existing research on the mechanism of extravascular stents in preventing restenosis of grafted veins. Furthermore, we have developed a novel extravascular stent for the prevention and treatment of restenosis. This will help optimize the clinical treatment plan of external stents and improve the prognosis in patients with vein grafts.

SUCCESSFUL RESOLUTION OF NUTCRACKER SYNDROME WITH 3D PRINTED PEEK EXTRAVASCULAR STENT IN AN ADOLESCENT BOY.

Three-dimensional printed polyetheretherketone (PEEK) extravascular stent was applied to treat a 14-year-old boy with nutcracker syndrome. Digital subtraction angiography revealed a segment of the left renal vein (LRV) with reduced contrast filling immediately before its inflow into the inferior vena cava, and high-pressure gradient. The three-dimensional reconstruction model demonstrated that the LRV and the duodenum were contracted at the aortomesenteric angle, resulting in LRV compression from the abnormal high-level duodenal compartment. When duodenum courses between the abdominal aorta and superior mesenteric artery (duodenal interposition), the LRV entrapment occurs even at <90 aortomesenteric degrees. Three-dimensional printed PEEK extravascular stent was chosen to elevate the superior mesenteric artery and lower the duodenum position, thus relieving LRV compression. This extravascular application has significant advantages over open surgery, endovascular stenting and artificial vessel procedures with expanded polytetrafluoroethylene. It provides better cellular vitality by ensuring soft tissue proliferation. By reducing external acceleration and centrifugal force, a three-dimensional printed PEEK extravascular stent reduces adverse side effects. Such a stent has a distinctive personalized design, good stiffness, and durability that allows blood vessel growth, preventing stent migration and thrombosis. Therefore, it is suitable for both adult and pediatric patients. According to the abdominal ultrasound and multi-slice computed tomography scan, the postoperative follow-up results were satisfactory one year after surgery. The patient felt well, the blood flow in the LRV was not obstructed, and the blood flow velocity was average. The external stent was in place.

3D-Printed PEEK Extravascular Stent in the Treatment of Nutcracker Syndrome: Imaging Evaluation and Short-Term Clinical Outcome.

Minimally invasive options are safe and reliable alternatives for the treatment of nutcracker syndrome (NCS). After continued efforts, our team successfully devised a new and effective therapeutic method: 3D-printed extravascular stenting of the left renal vein. From December 2017 to May 2019, 28 patients (25 men and 3 women) from different parts of China between 18 and 37 years old (mean, 23.6 years) diagnosed with NCS were admitted for laparoscopic 3D-printed extravascular stenting treatment. The post-operative follow-up duration was 6-24 months (median, 16.3 months). Technical success of the operation was achieved in all patients. After treatment, the NCS symptoms all patients resolved or improved during the follow-up period, without relapse. Most symptoms, including macro-/microhematuria, proteinuria, and flank/abdominal pain, tended to resolve within 3-6 months after the surgery; other symptoms, such as left-sided varicocele, also showed varying degrees of improvement at different times post-operatively. Perioperative complications were noted in two patients, including transient and mild lymphatic leakage, without any adverse effects. All extravascular stents were visualized on computed tomography and Doppler ultrasound scans, and no migration or any side effects occurred during the entire follow-up period. Compared to endovascular stenting or polytetrafluoroethylene artificial vessel procedures, 3D-printed polyetheretherketone extravascular stenting has more advantages in terms of stent design and rigidity and approach rationality while successfully preventing stent migration and thrombosis. Therefore, this method may serve as an accurate and effective treatment for NCS patients.

A minimally invasive alternative for the treatment of nutcracker syndrome using individualized three-dimensional printed extravascular titanium stents / 中华医学杂志(英文版)

Background@#This study was designed to evaluate the clinical and radiographic outcomes of patients with nutcracker syndrome (NCS) who were treated with three-dimensional printing (3DP) extravascular titanium stents (EVTSs). The 3DP EVTS was expected to release the hypertension of the left renal vein (LRV) produced by its compression between the superior mesenteric artery (SMA) and the aorta without causing any complications.@*Method@#The pre-operative kidney model of each patient was printed out to enable surgical planning. After that, the EVTS was designed based on the LRV’s primitive physiologic structure using computer-aided design software, and each stent was printed out with a precision setting of 20 μm. Seventeen patients who had been suffering from NCS underwent laparoscopic 3DP EVTS placement. The surgical procedure was designed for the placement of EVTS, taking great care in positioning and fixing the stent. Surgical data, which included patient demographic characteristics as well as pre- and post-operative test results, were collected and analyzed.@*Results@#The mean duration of surgery was 75 ± 9 min, and the mean blood loss was 20 ± 5 mL. Computed tomography examinations revealed that the pre- and post-operative angle between the SMA and the aorta ranged from 18.7° ± 4.3° to 48.0° ± 8.8° (P < 0.05); in patients with left varicocele, the mean diameter of the left spermatic vein ranged from 3.7 ± 0.5 to 1.3 ± 0.2 mm (P < 0.05). Moreover, Doppler ultrasound examinations showed that the peak velocity of blood flow at the hilar area ranged from 12.4 ± 3.3 to 18.5 ± 3.4 cm/s (P < 0.05). No side effects were observed in the 24 to 42 months following surgery.@*Conclusion@#The findings after 2 years of follow-up suggest that the 3DP EVTS is a safe and effective minimally invasive alternative for the treatment of NCS.

Robot-assisted laparoscopic extravascular stent for nutcracker syndrome.

Minimally invasive treatment options are a safe and feasible alternative for treatment of nutcracker syndrome. Endovascular stenting has shown promising long-term resolution of symptoms but can be complicated by stent migration or thrombosis. Laparoscopic extravascular stent placement has shown promising results with the potential to avoid these complications. We report the first case of extravascular stent placement using the robotic approach for the treatment of nutcracker syndrome.

Safety and efficacy of laparoscopic three-dimensional printed extravascular stent placement for nutcracker syndrome / 中华泌尿外科杂志

Objective To assess the safety and effectiveness of laparoscopic implantation of three-dimensional (3D)-printed extravascular stent for treatment of nutcracker syndrome (NCS).Methods The clinical data of NCS in our hospital were prospectively collected from August 2015 to August 2016.Doppler ultrasound and CT examination were performed before the operation of all the patients who were in line with the diagnostic criteria of NCS.The 3D model of extravascular stents with especial device to prevent migration was designed and was made by 3D metal printer with titanium alloy.The left renal vein(LRV) was exposed completely up to the inferior vena cava,then the stent was placed around the compressed LRV.Results 10 patients were enrolled in the study,including 9 males and 1 females,age (21.5 ±4.6) years.Among these patients,there were 4 cases with severe hematuria,1 case with proteinuria,5 cases with left lumbago,and 5 cases with left severe varicocele.The preoperative doppler ultrasound examination showed the diameter of the the compressed LRV was (1.57 ± 0.25) mm,and flow velocity was (164.40 ± 55.27) cm/s;the diameter of the LRV at the renal hilum was (8.7 ± 1.59) mm,and flow velocity was (10.70 ± 2.21) cm/s.The average operation time was (75 ± 11) min,and the average hospital stay after operation was 7 d.All symptoms were relieved at 3-7 d after operation.All patients were asymptomatic and all stents were stable after follow-up.At 12 months after surgery,the diameter of the LRV at the renal hilum was (8.23 ± 1.90) mm on doppler ultrasound,and there was significant decrease (P ＜ 0.01);the flow velocity was (21.20 ±3.88) cm/s,and there was significant increase (P ＜ 0.01).Conclusions Laparoscopic three-dimensional printed extravascular stent placement is a safe,effective and minimally invasive technique for treatment of NCS.

Retroperitoneal laparoscopic extravascular stent placement for nutcracker syndrome / 中华泌尿外科杂志

Objective To report our experience of retroperitoneal laparoscopic extravascular stent placement for nutcracker syndrome.Methods The clinical data of 12 nutcracker syndrome patients (10 males and 2 females;mean age 26 years) who underwent retroperitoneal laparoscopic extravascular stent placement from March 2014 to Febuary 2016 were retrospectively reviewed.The main symptoms were gross hematuria in 8 patients(one with proteinuria)and flank pain was noted in 1 patient.Three male patients had left-sided secondary varicoceles.Ultrasonography and computed tomography showed the left renal vein clamped by the superior mesenteric artery and the aorta.The anteroposterior diameter of the left renal vein in the renal hilum was three-fold than the aortomesenteric area,and the peak velocity ratio of the aortomesenteric area was much faster than the renal hilum.Twelve patients underwent laparoscopic extravascular stent placement under general anesthesia.The preaortic fibrous tissue between the aorta and the superior mesenteric artery was released intraoperatively.Renal vein became fiat when the superior mesenteric artery was elevated.The 6-8 cm extravascular stent was set on the surface of the renal vein to prevent the compression.Results Stenting was successfully accomplished in all 12 patients.Mean operative time was 62 min (50-125 min),estimated blood loss was 35 ml(20-100 ml),and the hospital stay after operation was 8 days (6-12 days).Three patients had a transient orthostatic intolerance,and they were cured by conservative treatment.With a mean follow up of 14 months (5-30 months),symptoms of hematuria and flank pain resolved in 7/8 and 1/1,respectively.Varicoceles were cured in all three patients.One case got partial relief because of recurrent hematuria due to excessive exercise.Ultrasonography showed that extravascular stent was in the right place,and the angle between abdominal aorta and superior mesenteric artery became normal.The inner diameter of left renal vein was decreased,and the narrow segment was diminished in diameter meanwhile the blood outflow was smooth.Conclusions Retroperitoneal laparoscopic extravascular stent placement in the renal vein is a safe and effective approach for nutcracker syndrome.

Laparoscopic management for Nutcraker Syndrome with resection of fibrous ring and placing extravascular stent: a report of 5 cases and review of the literature / 中华泌尿外科杂志

Objective To investigate the Laparoscopic management for Nutcraker Syndrome(NCS) with resection of fibrous ring and placing extravascular stent.Methods This was a retrospective analysis of clinical data and treatment process of cases from March 2010 to February 2015 in urology department,affiliated hospital of Guizhou medical university.Five cases with NCS,4 males and 1 female;age were 28-40 years,mean age was 35 years,all cases were afflicted with gross hematuria and flank pain,the history of gross hematuria were 6-72 months.3 cases were afflicted with proteinuria.Duplex ultrasound scanning before surgery revealed the compressed left renal vein (LRV) between the aorta and the superior mesenteric artery(SMA),with peak velocity 110-132 cm/s,an average of 121 cm/s.The flow velocity of LRV in the renal hilum were 18-25 cm/s,an average of 21 cm/s.CT scanning showed that the stricture segment diameter of LRV were 1.2-2.5 mm,an average of 1.8 mm;and the max diameter of proximal dilatation of the LRV in renal hilum were 8.3-15.2 mm,an average of 10.1 mm.The ratio between the dilated segment inner diameter and the stricture segment were 3.4-9.5.Bleeding from the left ureteral orifice was detected by cystoscopy in 3 cases.5 cases were treated by resection of fibrous ring and placing extravascular stent with Laparoscopic management,and the average length of extravascular stent was 4.0 cm.Results The operation was successful in the 5 cases.The average operation time was 83 min.The average blood loss was 65 ml.Hematuria gradually reduce 5-6 days and resolved 7-20 days after surgery in 5 patients.Proteinuria was disappeared successful 2 weeks after surgery in 3 patients.There was no recurrence at 8-24 months' follow-up.3 days after surgery Doppler ultrasound showed the stricture segment diameter of LRV were 3.8-5.6 mm,an average of 4.9 mm;the ratio between the dilated segment inner diameter and the stricture segment decreased were 1.1-2.0,an average of 1.6;the peak velocity of compressed LRV were 25-45 cm/s,an average of 34 cm/s.6 months after surgery,CTA result showed no LRV compression in the aortomesenteric region;the max diameter of LRV in renal hilum were 7.9-9.8 mm and 6.0-8.8 mm in the aortomesenteric region of LRV.Conclusion Etiology of NCS exist a fibrous ring around the left renal vein outflow of the inferior vena cava besides the commonly anatomic extrinsic compression on the LRV as it crosses between the superior mesenteric artery and the aorta.The Laparoscopic management for NCS with resection of fibrous ring and placing extravascular stent is an effective minimally invasive treatment.

Laparoscopic left renal vein extravascular stenting for treatment of left renal vein entrapment syndrome / 中华泌尿外科杂志

ObjectiveTo investigate the surgical management of left renal vein entrapment syndrome.MethodsEight cases with left renal vein entrapment syndrome (5 males and 3 female ; mean age 26 years) with history of gross hematuria for 3 to 46 months were reviewed.Doppler ultrasound reports suggested compression of the left renal vein at mesenteric angle in all cases.And the dilated segment of the left vein was three-fold than the stricture segment in diameter.CT scan showed the abnormal angle between aorta and superior mesentery artery in all cases.Bleeding from the left ureteral orifice was detected by cystoscopy in 6 cases.We treated 8 patients by extravascular stent immobilization with laparoscope.ResultsThe operation was successful in the 8 cases without surgical complications.The average operation time was 63 min.The average blood loss was 14 ml,and the average hospital stay after operation was 6 days.Follow-up of 3 -20 months,there was no hematuria relapse since been relieved in 7 cases,one case remained microscopic hematuria.Color Doppler ultrasound examination in all 8 cases showed the narrowest inner diameter of left renal vein was 7.4 mm (6.5 - 8.7 mm),the blood flow was smooth.The angle between abdominal aorta and superior mesenteric artery become normal.Conclusions Laparoscopic left renal vein extravascular stenting could be a new surgical method to treat left renal vein entrapment syndrome.The method of putting artificial blood vessel around renal vein is simple,safe and effective.