Left renal vein transposition for nutcracker syndrome

Objective: Nutcracker syndrome, caused by compression of the left renal vein (LRV) between the superior mesenteric artery and the aorta, results in left renal and gonadal venous hypertension. Several treatment options have been described to relieve associated symptoms. The purpose of this study was to evaluate late results of LRV transposition and identify risk factors affecting outcomes. Methods: Clinical data from 23 consecutive patients diagnosed with nutcracker syndrome from January 1996 to October 2007 were retrospectively reviewed. Results: There were 10 males and 13 females (median age 22 years; range, 14-67) with radiologic evidence of LRV compression. On ultrasound evaluation (15/23 patients), the mean ratio of LRV peak systolic velocity measured at the site of compression and the renal hilum was 7.3 (range, 2.5-12). On venography (14/23 patients), the mean renocaval pressure gradient was 4 mm Hg (range, 2-6 mm Hg). Twelve patients with atypical abdominal pain (n = 4), hematuria (n = 5), and varicocele (n = 6) were managed expectantly. Eleven patients underwent LRV transposition through a transperitoneal exposure. Symptoms in these patients included left flank pain (n = 10), hematuria (n = 7), and varicocele (n = 3). In 2/11 patients, the LRV was found to be occluded at operation. There were no early postoperative complications. Most conservatively managed patients remained stable or improved over a mean follow-up period of 26 months (range, 0.2-59 months). Two patients were lost to follow-up at our institution and ultimately underwent intervention with LRV stenting and autotransplantation elsewhere. One patient was diagnosed with thin basement membrane disease on renal biopsy. Five patients with varicocele remained asymptomatic; 1 underwent local repair. Over a mean follow-up of 39 months (range, 0.13-144 months) in surgically managed patients, symptoms of flank pain and hematuria resolved or improved in 8/10 and 7/7, respectively. Varicoceles recurred in 2/3 patients in spite of resolution of flank pain. Both preoperatively occluded LRVs rethrombosed; one underwent thrombolysis with stenting, the other reimplantation of the left gonadal vein into the IVC. Conclusion: Evaluation of the clinical significance of radiologic LRV compression remains challenging, as does selection of patients for intervention. LRV transposition is a safe, effective procedure in selected patients with persistent, severe symptoms. Patients with progression to occlusion of the LRV should be considered for alternative therapeutic procedures. Varicoceles, in the setting of nutcracker syndrome, may need independent repair.