Pelvic Nerve Neuropathy After Kidney Transplantation M. Nikoobakht, A. Mahboobi, A. Saraji, A. Mehrsai, A. Emamzadeh, M.T. Mahmoudi, and G. Pourmand ABSTRACT Objectives. We examined the relation of various age, gender, diabetes, hypertension, and graft function with the prevalence of femoral and lateral cutaneous nerves sensory and/or motor disturbances after kidney transplantation. Materials and Methods. Among 129 patients who underwent kidney transplantation from April 2001 to March 2002. We excluded, 10 due to preoperative sensory disturbances. We evaluated the prevalence of sensory and/or motor disturbances preoperatively by physical examination and postoperatively by both physical and electromyography examinations. The cinical findings were correlated with the following risk factors: age, gender, preoperative dialysis duration, background diseases. (e.g., diabetes, hypertension), graft weight, nephron mass index, operative and retraction time, and rejection episodes. Results. At 1 to 9 days postoperatively, 31 ng (26%) patients, suffered neuropathy of the lateral cutaneous nerve and 4 (3.3%), femoral neuropathy. No meaningful relation was detected between the incidence of neuropathy and these risk factors. The probability of neuropathy was greater among diabetics, hypertensives, women, and those with graft rejection episodes. All of these complaints were temporary. Conclusions. Post-kidney transplant femoral and/or lateral cutaneous nerve neuropathy is a prevalent complication particularly in diabetic, hypertensive, and female patients. Neuropathy is also more evident after graft rejection. S ENSORY (and/or motor) disturbances in the thigh after kidney transplantation is a relatively prevalent complaint.1 Kidney transplantation improves life quality among patients suffering end-stage renal disease. Still, some problems may occur after kidney transplantation that influence the life quality, presently an important facet of disease treatment. The lateral cutaneous nerve of the thigh (LCNT) originates from the roots of L2 and L3 progressing through the lateral anterior thigh from the inguinal ligament to the knee. Slight numbness, tenderness, and sometimes pain may occur when it is damaged. Touch and needle perception are decreased.2 The femoral Nerve (FN) includes nervous roots of L2, L3 and L4. It has two sensory and motor parts. It expands through the pectineous, sartorius, and quardriceps muscles and mediates inner anterior surface sensation in the thigh and foreleg. Damage causes hyposthesia, paresthesia, pain in the anterior and inside thigh and foreleg, together with a feeling of weakness when the knee is bent.2 This prospective study sought to describe the prevalence of these side effects and study the probable risk factors. MATERIALS AND METHODS Among 129 kidney transplants from April 5, 2002, to March 19, 2003, we excluded 10 patients who showed cerebral apoplexy, before thigh neuropathy or sensory disturbance. Patients underwent neurologic investigations 1 day before as well as 1 day and 1 week after transplant, including description and physical examination for the LCNT and FN. The lateral and anterior thigh power hip flexion and knee extension as well as knee reflexes. Whenever the clinical evaluation was positive, suggesting confirmation of the diagnosis, as well as electromyography, and nerve conduction velocity studies were performed during the second week. We recorded age (in years), gender, dialysis time (in months), diabetes record, hypertension record, height (in meters), weight (in kg), anastomotic time (time necessary from the beginning of anastomosis up to removal of clamp), retractor time (from placement to removal of retractor), operation time (from the beginning of From the Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran. Address reprint requests to M. Nikoobakht, Urology Research Center, Sina Hospital, Hasan Abad SQ, Tehran, Iran. E-mail: nikoobakht_m@hotmail.com 0041-1345/07/$–see front matter doi:10.1016/j.transproceed.2007.03.085 © 2007 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710 1108 Transplantation Proceedings, 39, 1108 –1110 (2007) PELVIC NERVE NEUROPATHY 1109 incision up to complete skin suture in minutes) and transplanted kidney weight. Plasma creatinine level on the third day after operation together with that at discharge (in mg/dL) and episodes of rejection were recorded. During the first week after transplantation, ultrasonography of kidney was performed to evaluate the existence or not of a collection around the kidney. The calculation method for the nephron mass index was as follows: weight of transplanted kidney(g)/BMI and BMI was calculated as: (kg) wigth/(m*m) height. Logistic regression analysis was used for data analysis. RESULTS Mean patient age was 40.45 years. The 119 patients included 80 men and 39 women. From among 119 patients, 35 were suffering from neuropathy (29.4%), 31 of which were related to LCNT (26.05%), and 4 to FN (3.36%). Among patients suffering from femoral neuropathy, paresis was observed in 100% of patients, but none was affected by paralysis. Pain, paresthesia, and hypesthesia were observed in 100%, 50%, and 100% of patients, respectively. Considering neuropathy of the LCNT nerve, pain with irritation was observed among 22.58% with paresthesis and hypesthesia in 74.19% and 96.77% respectively. The scope of time to appearance was 1 to 9 days, the median of which was 1 day and mean, 1.6 days. Risk factors were not statistically analyzed among patients suffering from the femoral disorder due to the small number of persons affected. But diabetes was not seen among these patients; 25% had rejection and 50%, hypertension. Neuropathy of the thigh and LCNT neuropathy is shown in Tables 1 and 2. No variable increased neuropathy meaningfully, but in special cases, these were interacting odds ratios. Increased Table 1. Sensory Disturbance in the Thigh After Renal Transplantation Evaluating Possible Predisposing Factors Variable P Value Odds Ratio 95% Confidence Interval Age Gender Duration of dialysis Height Weight Diabetes Hypertension Deaver time Anastomtic time Warm ischemia Cold ischemia Local atherosclerosis Transplanted kidney weight Nephron mass index Creatinine day 3 Creatinine at discharge Antilymphocyte globulin Rejection Acute tubular necrosis Collection volume around transplanted kidney .7090 .5127 .6620 .8465 .6305 .2459 .1344 .372 .0891 .1413 .1962 .8041 .6293 .3349 .0118 .1384 .4533 .4175 .1662 .3483 .994 .709 .996 1.534 .993 1.966 1.467 .989 .963 .816 .977 .889 1.003 1.108 1.050 .202 .72 1.471 .398 .998 .961–1.27 .332–1.735 .978–1.0114 .020–116.885 .965–1.022 .628–6.157 .663–3.247 .965–1.013 .921–1.006 .623–1.07 .644–1.012 .350–2.255 .990–1.017 .900–1.364 .907–1.216 .942–1.532 .305–1.699 .579–3.741 .108–1.466 .994–1.002 Table 2. Neuropathy of Lateral Cutaneous Nerve of the Thigh: Evaluating Possible Predisposing Factors Variable P Value Odds Ratio 95% Confidence Interval Age Gender Duration of dialysis Height Weight Diabetes Hypertension Deaver time Anastomtic time Warm ischemia Cold ischemia Local atherosclerosis Transplanted kidney weight Nephron mass index Creatinine day 3 Creatinine at discharge Antilymphocyte globulin Rejection Acute tubular necrosis Collecetion volume around transplanted kidney .4469 .6446 .5269 .917 .3130 .1605 .3217 .1803 .0771 .1054 .1142 .9292 .9273 .986 .815 .994 1.274 .984 2.28 1.523 .983 .966 .789 .972 1.044 1.001 .952–1.022 .342–1.942 .976–1.013 .013–121.549 .955–1.015 .721–7.207 .663–3.500 .958–1.008 .919–1.004 .591–1.051 .938–1.007 .406–2.682 .987–1.015 .2547 .6586 .1809 .730 .4303 .239 .4300 1.13 1.034 1.177 .857 1.478 .455 1.007 .913–1.412 .892–1.199 .927–1.495 .357–2.057 .560–3.906 1.123–1.686 .989–.026 age did not increase neuropathy risk. Neuropathy was 1.32 times more prevalent in women. Dialysis time, weight, and height had no effect on appearance of these side effects. Times of anastomosis and retractor do not increase the risk. Diabetes added 1.96 times and hypertension 1.46 times to the risk. The weight of the transplanted kidney showed no effect on the occurrence of neuropathy. Nephron mass index had no effect. Rejection added 1.47 times to the risk and creatinine at discharge added 1.2 fold. However, none of these factors was significant. DISCUSSION Neurologic complications are frequent among renal transplant recipients and may contribute to morbidity. Acute femoral neuropathy may occur in about 2% of patients as a result of nerve compression after the operation.1 It also may be due to the uremic state of renal failure.2 For this reason, we excluded 10 patients who had sensory disturbances in the thigh before transplantation. According to our study, the rate of sensory disturbance of the femoral nerve was 29.4% of which 26.05% were related to the LCNT and 3.36% to the FN. Certain mechanisms have been proposed for complete FN palsy or ischemia, such as clamping the internal iliac artery or steal phenomenon.3 There may be direct surgical damage to the vessels supplying the femoral nerve4 or direct compression of the femoral nerve by the transplanted kidney, by a self-retractor or by a hematoma.6,7 Vaziri et al8 demonstrated compression of the FN retaining by the medial and inferior blade of self-retaining retractors during renal transplantation as the cause of femoral neu- 1110 ropathy after renal transplantation; in our study, retractor time was not increased. Other studies about diabetes and neuropathy have suggested that it is a risk factor for postoperative sensory disturbances of the thigh.3,5 After excluding diabetic patients with preexistent neuropathy, diabetes was shown to increase the probability of LCNT neuropathy 2.28 times and thigh neuropathy 1.96 times, although these values were not significant. Diabetes may predispose to this side effect. Larger studies should be performed. Uremia has been proposed to be an important factor,4 but the present study failed to reveal a meaningful relation between disease time, dialysis time, and neuropathy. In patient with acute rejection, neuropathy in the thigh was 1.47 times higher. Immunologic mechanisms or increased lymphatic flow may be responsible. Creatinine at discharge BMI, and nephron mass index did not show significant relations with this side effect. Weight of the kidney had no effect. Hypertension and female gender increased femoral neuropathy risk by 1.47 and 1.32, respectively. NIKOOBAKHT, MAHBOOBI, SARAJI ET AL In conclusion, the incidence of femoral neuropathy after renal transplantation was 3.36 in our study with increased incidence among women, diabetics, and hypertensives.9 REFERENCES 1. Murata Y, Sakamoto K, Hayashi R, et al: Sensory disturbance of the thigh after renal transplantation. J Urol 165:770, 2001 2. Ropper AH, Brown RH: Adams and Victor’s Principles of Neurology, 8th ed. New York: McGraw Hill; 2005, p. 271 3. Jog MS, Turely JE, Berry H: Femoral neuropathy in renal transplantation. Can J Neurol Med Sci 21:38, 1994 4. Yasbeck S, Larbrissen A, O’Regan S: Femoral neuropathy after renal transplantation. J Urol 134:720, 1985 5. Sharma KR, Cross J, Santiago F, et al: Incidence of acute femoral neuropathy. Arch Neurol 59:541, 2002 6. Sisto D, Chin WS, Geelhoed GW, et al: Femoral neuropathy after renal transplantation. South Med J 73:1464, 1980 7. Meech PR: Femoral neuropathy following renal transplantation. Aust NZ J Surg 60:117, 1990 8. Vaziri ND, Barton CH, Ravikumar GR, et al: Femoral neuropathy: a complication of renal transplantation. Nephron 28:30, 1981 9. Vaziri ND, Barnes J, Khosrow M, et al: Compression neuropathy subsequent to renal transplantation. Urology 7:145, 1976