Persistent Leak Research Articles

Endoscopic therapy for biliary strictures complicating living donor liver transplantation: Factors predicting better outcome.

AIMTo identify factors predicting outcome of endoscopic therapy in bile duct strictures (BDS) post living donor liver transplantation (LDLT).METHODSPatients referred with BDS post LDLT, were retrospectively studied. Patient demographics, symptoms (Pruritus, Jaundice, cholangitis), intra-op variables (cold ischemia time, blood transfusions, number of ducts used, etc.), peri-op complications [hepatic artery thrombosis (HAT), bile leak, infections], stricture morphology (length, donor and recipient duct diameters) and relevant laboratory data both pre- and post-endotherapy were studied. Favourable response to endotherapy was defined as symptomatic relief with > 80% reduction in total bilirubin/serum gamma glutamyl transferase. Statistical analysis was performed using SPSS 20.0.RESULTSForty-one patients were included (age: 8-63 years). All had right lobe LDLT with duct-to-duct anastomosis. Twenty patients (48.7%) had favourable response to endotherapy. Patients with single duct anastomosis, aggressive stent therapy (multiple endoscopic retrograde cholagiography, upsizing of stents, dilatation and longer duration of stents) and an initial favourable response to endotherapy were independent predictors of good outcome (P < 0.05). Older donor age, HAT, multiple ductal anastomosis and persistent bile leak (> 4 wk post LT) were found to be significant predictors of poor response on multivariate analysis (P < 0.05).CONCLUSIONEndoscopic therapy with aggressive stent therapy especially in patients with single duct-to-duct anastomosis was associated with a better outcome. Multiple ductal anastomosis, older donor age, shorter duration of stent therapy, early bile leak and HAT were predictors of poor outcome with endotherapy in these patients.

Huge Mastoid Cholesteatoma with Skull Base Erosion and CSF Leak

Persistent CSF leakage was identified during an extensive mastoidectomy. The complication was rectified by grafting a collagen matrix graft over the leak.

Experience of Pleurodesis with a 50% Glucose Solution in Patients with Secondary Pneumothorax: A Case Series

Secondary pneumothorax commonly encountered and it often recurs or becomes a refractory to treatment. Pleurodesis is usually selected for initial treatment in community hospitals. Recently, endobronchial intervention using the endobronchial Watanabe spigot and endobronchial valve for refractory pneumothorax has become available, but these procedures can be performed only at a few institutions with sufficient staff and equipment. The use of a glucose solution for pleurodesis has been reported as a novel approach to persistent air leakage. Pleurodesis with a 50% glucose solution was occasionally empirically performed in community hospitals. However, only limited literatures have published. Here, I report the experience of five patients (4 men and 1 woman; 71 years to 84 years old), seven times with inoperable secondary pneumothorax who received pleurodesis with a 50% glucose solution. In our cases, two of them had pneumoconiosis, one had chronic obstructive lung disease (COPD), one had interstitial pneumonia (IP) and one had lung cancer. The procedure successfully stopped air leakage and allowed chest tube removal (4 days to 10 days) in three patients without severe complications. Same as previous report, temporary hyperglycemia occurred in three patients. Therefore, pleurodesis with a 50% glucose solution suggested possibility that a feasible and safe. Despite future large-scale studies should aim to examine the efficacy and tolerance of this technique, it would be beneficial to obtain the alternative agent of pleurodesis for patients with inoperable secondary pneumothorax and rural hospitals.

Persistent Laser-Induced Leakage in a 20 nm Charge-Pump Phase-Locked Loop (PLL)

A persistent loss-of-lock error was experimentally observed in a 20 nm charge-pump phase-locked loop (PLL). Through circuit modeling and simulation, the observed error was attributed to a non-recoverable off-state leakage increase resulted from two-photon absorption (TPA) laser-induced damage. The laser-induced damage is consistent with results from 28 nm bulk transistors.

Thoracoscopic Surgery for Pneumothorax Following Outpatient Drainage Therapy.

We investigated the outcomes of surgery for pneumothorax following outpatient drainage therapy. We reviewed the records of 34 patients who underwent operations following outpatient drainage therapy with the Thoracic Vent at our hospital between December 2012 and September 2016. Indications for outpatient drainage therapy were pneumothorax without circulatory or respiratory failure and pleural effusion. Indications for surgical treatment were persistent air leakage and patient preference for surgery to prevent or reduce the incidence of recurrent pneumothorax. Intraoperatively, 9 of 34 cases showed loose adhesions around the Thoracic Vent, all of which were dissected bluntly. The preoperative drainage duration ranged from 5 to 13 days in patients with adhesions and from 3 to 19 days in those without adhesions, indicating no significant difference. The duration of preoperative drainage did not affect the incidence of adhesions. The operative duration ranged from 30 to 96 minutes in patients with adhesions and from 31 to 139 minutes in those without adhesions, also indicating no significant difference. Outpatient drainage therapy with the Thoracic Vent was useful for spontaneous pneumothorax patients who underwent surgery, and drainage for less than 3 weeks did not affect intraoperative or postoperative outcomes.

Is it Necessary to Perform Nephrostography before Tube Removal after Percutaneous Nephrolithotomy.

Background:The aim of this study is the caparison of the complications rate among the patients which underwent nephrostomy removal with and without performing nephrostography.Materials and Methods:Between October 2010 and November 2011, 200 patients who underwent standard percutaneous nephrolithotomy (PCNL) procedures were included in this study. The patients were randomly assigned into two groups, Group A (n = 100) did not undergo the antegrade nephrostography on postoperative day 2 and the patients were discharged keeping the nephrostomy until postoperative day 3, while in Group B (n = 100) the nephrostomy tube was removed on postoperative day 3 after antegrade nephrostography demonstrating ureteral drainage down to the bladder. Postoperative complications in both groups were recorded and compared between two groups.Results:A total of 200 patients were treated with standard PCNL. The persistent leakage of urine after removal of the nephrostomy tube was encountered in 5 (5.0%) and 3 (3%) of patients in Groups 1 and 2, respectively. Urinary leakage was resolved with conservative management in 3 and 2 patients of Groups 1 and 2, respectively, but a double-J stent was inserted in 2 and 1 patients in each group because of persistent leakage of urine more than 1-week. The two groups show comparable complications such as prolonged urinary leakage which managed in a similar manner, however, postoperative hospital stay was lesser in Group 1.Conclusion:Our results revealed postoperative performing nephrostogramy before tube removal changed the planning of complications such as prolonged urinary leakage and could be omitted in cases.

PUB148 Efficacy of Heimlich Valve in Preventing Air Leaks

One of the most common complications after a lung reduction surgery is prolonged air leak. This is a prospective study, which reports the routine use of Hiemlich valve and its impact on total hospital stay and a reoperation for a persistent leak. This article evaluates a type of treatment for air leaks using Hiemlich valves; the results also show a prospective algorithm for treatment of persistent air leaks. From September 2005, through November 2011, 150 patients were operated for elective pulmonary resection, which had a heterogenous pattern of lung disease, with post-operative mortality of 4 patients and average duration of total length of hospital stay of 10.61 days. Bilateral Hiemlich valves were applied to 18 patients, and unilateral Hiemlich valves in 132 patients. Dyspnea increased in 10 patients after switching to Heimlich valve and they were resumped on chest drainage with suction.Use of Heimlich valve was done irrespective of size of air leak. Grading of air leak was done as small defined if an occasional bubble was seen; moderate when frequent bubbles were seen or large if the bubbles were continuous in the water seal chamber. X-rays were obtained in patients after Hiemlich valve was placed which showed minimal size of air leak. Patients did not develop dyspnea after placement of Hiemlich valve. Follow up x-rays in all of the cases after removal of Hiemlich valve showed completely resolved apical air spaces. Mean number of postoperative days to placement of the Hiemlich valve was 7.2 ± 2.4. The mean number of days to postoperative discharge was 8.1 ± 1.6(range5 to 16) and the mean number of days after discharge until removal of the chest tubes and the Hiemlich valves was 3.61 ± 1.4(range 0, to 26). Almost all patient tolerated Hiemlich valve well after discharge. The average hospital stay was shortened by 56% with the use of Hiemlich valve in patients who underwent lung reduction surgery, considering the fact that all these patients would have stayed in the hospital, till the removal of their chest tube. The mean length of hospital stay was 11 days. The reduced hospital stay has certainly been caused by the use of Hiemlich valve. It is advisable to put chest drainage system to Hiemlich valves, as early as the third post-operative day. This eventually helps in providing better patient care.

Left Atrial Appendage Closure With the New Occlutech® Device: First in Man Experience and Neurological Outcome.

Percutaneous left atrial appendage closure (LAAC) is a valuable treatment option for stroke prevention in patients with atrial fibrillation and a HAS-BLED-Score ≥3. Determinants of procedural safety events and neurological outcome of the patients with the Occlutech device (OD) are not established yet. Between 2012 and 2016, 30 patients underwent LAAC using the OD. This is a prospective study. Neurological examination and transesophageal echocardiography was performed directly before and after the procedure and after 1, 3, and 12 months. The OC was successfully implanted in 28 of the 30 enrolled patients (93%). Two patients presented a hemodynamic relevant pericardial effusion. A leak <3 mm could be documented direct after implantation in 4 patients. After 3 months, there were only 2/4 patients with persistent LAA leakage with a maximum leakage of <3 mm. The correct position of the device was confirmed in 27/28 patients during 3-month follow-up. In 2 patients, there was a thrombus at the OC. In 12 patients, a transoesophageal echocardiography was performed after 12 months. All patients (12/12) showed a correct placement of the device. None of the patients developed a clinically apparent stroke or died during follow-up. In this uncontrolled, nonrandomized study, acute and 3-month follow-up success of LAAC using OD was high. No patient showed significant neurological deficits.

Management of a persistent staple line leakage with Roux-en-Y fistulojejunostomy following sleeve gastrectomy

Management of a persistent staple line leakage with Roux-en-Y fistulojejunostomy following sleeve gastrectomy

Linear Frontal Bone Fractures - Clinical and Surgical Profile: A Retrospective Study

Background: Linear frontal bone fractures are common injuries in road traffic accidents. Pneumocephalus and CSF (cerebrospinal fluid) leak are both factors influencing their outcome. Persistent pneumocephalus and CSF leak are main indications for surgical treatment. Objectives: Surgical indications are rarely discussed in linear frontal bone fractures. We report results on patients with linear frontal bone fractures, clinical data, management, surgical indications and outcome. Methods: From 2011 to 2015, 121 patients were admitted to our institution with a diagnosis of frontal bone fractures (compound depressed fractures excluded). Fractures were classified into three types, Type A: fracture involving anterior wall of the frontal sinus; Type B: fracture involving posterior wall of the frontal sinus and Type C: fracture of frontobasal region without involving the frontal sinus. All patients were followed for more than 6 months. Results: A total of 112 patients were conservatively treated with standard pneumocephalus protocol. Nine patients underwent surgical intervention. The indications for surgery were the presence of persistent pneumocephalus in CT scan and persistent CSF leak. The presence of pneumocephalus or CSF leak in Type B patients sinus cranialisation with repair of the defect were the variables mainly influencing the outcome (P < 0.001). Conclusions: Frontal bone fracture needs careful attention to prevent its complications such as a CSF leak and meningitis. Patients need clinical and radiological evaluation. Patients with persistent CSF leak or pneumocephalus should always be treated surgically and others should be managed conservatively

Gastroesophageal stenting for the management of post sleeve gastrectomy leak. A single institution experience.

ObjectivesTo retrospectively evaluate the effectiveness of gastroesophageal stenting for post sleeve gastrectomy staple line leaks using removable self-expandable stents.MethodsBetween April 2012 and June 2015, 12 consecutive patients (6 males) with mean age of 34 years: (21-38 years) presented with staple line leak 1-8 weeks after the operation (mean 2.8 weeks). Patients underwent gastroesophageal stenting by interventional radiology. A total of 23 stents were deployed with mean length of 17.8 cm (7-24 cm) and mean diameter 25.6 mm (18-36 mm). Stent re-insertion was needed in 7 patients (9 procedure), while 6 patients required percutaneous collection drainage and 3 patients required endoscopic glue injection with clipping. Two stent removal procedures were carried out under endoscopic visualization after failed stent capture under fluoroscopy, while the remaining stents were successfully removed by interventional radiology.ResultsStent placement was technically successful in all patients. Stent migration occurred in 6 patients (50%). There is a tendency for stent migration with shorter stent length (R= -0.557, p=0.008). The mean duration of stenting was 60.5 days (14-137 days). All patients underwent stent removal and resumed oral intake with no recurrence of leak at a mean follow up time of 190 days (14-410 days). Complications included gastrointestinal bleeding (n=1), proximal esophageal stricture (n=1) and stent occlusion (n=1).ConclusionGastroesophageal stenting as a primary measure after diagnosis of early post sleeve gastrectomy leak appears to offer a safe and effective alternative option in obviating repeat surgical interventions. Minimally invasive interventions may still be required for the management of persistent leak.

Posterior Fossa Spontaneous Cerebrospinal Fluid Leaks.

Describe the diagnosis and management of spontaneous lateral skull base cerebrospinal fluid (CSF) leaks that originate from the posterior fossa. Retrospective case review. Tertiary university hospital. Adult patients from 2005 to 2015 who underwent surgical repair of a spontaneous lateral skull base CSF leak with intraoperative confirmation of a posterior fossa leak source. Surgical repair. CSF leak resolution. Five patients had CSF leaks from the posterior fossa. The mean age at presentation was 54 years old (range, 19-79), the mean body mass index (BMI) was 32.6 (standard deviation [SD], 8.4), and the mean follow-up length was 34.6 months (SD, 19.4). Presentations did not differ from CSF leaks through middle fossa defects, including three patients with a history of meningitis and all patients with clear otorrhea following tympanostomy tube placement. All patients had resolution of the leak after surgical repair, but two patients required revision surgery for persistent leaks and one patient had a postoperative infection. Surgical approaches included one middle fossa, two transmastoid, one combined middle fossa/transmastoid, and one transcanal. Radiographic studies suggested a posterior fossa source in all cases but findings were often subtle. Posterior fossa CSF leaks represent a rare subset of spontaneous lateral skull base leaks. Diligent radiographic review and intraoperative assessment of the posterior fossa plate are crucial. The size and location of the defect dictates the optimal surgical approach. Surgeons should consider a posterior fossa source in failed repairs or when the initial surgery did not fully evaluate the posterior fossa plate.

Utility of endoscopic therapy in the management of Boerhaave syndrome.

Background/aims: The optimal intervention for Boerhaave perforation has not been determined. Options include surgical repair with/without a pedicled muscle flap, T tube placement, esophageal resection or diversion, or an endoscopic approach. All management strategies require adequate drainage and nutritional support. Our aim was to evaluate outcomes following Boerhaave perforation treated with surgery, endoscopic therapy, or both. Patients and methods: We performed a 10-year review of our prospectively maintained databases of adult patients with Boerhaave perforations. We documented clinical presentation, extent of injury, primary intervention, “salvage” treatment (any treatment for persistent leak), and outcome. Results were analyzed using the Fisher’s exact and Kruskal – Wallis tests. Results: Between October 2004 and October 2014, 235 patients presented with esophageal leak/fistula with 17 Boerhaave perforations. Median age was 68 years. Median length of perforation was 1.25 cm (range 0.8 – 5 cm). Four patients presented with systemic sepsis (two treated with palliative stent and two surgically). Primary endotherapy was performed for eight (50 %) and primary surgery for eight (50 %) patients. Two endotherapy patients required multiple stents. Median stent duration was 61 days (range 56 – 76). “Salvage” intervention was required in 2/8 (25 %) endotherapy patients and 1/8 (13 %) surgery patient (stent). All patients healed without resection/reconstruction. There were no deaths in the surgically treated group and two in the endotherapy group (stented with palliative intent due to poor systemic condition). Readmission within 30 days occurred in 3/6 of alive endotherapy patients (50 %) and 0/8 surgery patients. Re-intervention within 30 days was required for one endotherapy patient. Conclusion: Endoscopic repair of Boerhaave perforations can be useful in carefully selected patients without evidence of systemic sepsis. Endoscopic therapy such as stenting is particularly valuable as a “salvage” intervention. The benefits of endoscopic therapy and esophageal preservation are offset against an increased risk of readmission in patients primarily treated endoscopically.

Clinical prediction rule to determine the need for repeat ERCP after endoscopic treatment of postsurgical bile leaks

In patients who have undergone ERCP with biliary stenting for postsurgical bile leaks, the optimal method (ERCP or gastroscopy) and timing of stent removal is controversial. We developed a clinical prediction rule to identify cases in which a repeat ERCP is unnecessary. Population-based study of all patients who underwent ERCP for management of surgically induced bile leaks between 2000 and 2012. Multivariate and binary recursive partitioning analyses were performed to generate a rule predicting the absence of biliary pathology on repeat endoscopic evaluation. A total of 259 patients were included. On multivariate analysis, postsurgical normal alkaline phosphatase (ALP; OR, 2.26; 95% CI, 1.03-4.99), time from surgery to first ERCP< 8 days (OR, 2.47; 95% CI, 1.15-5.31), and minor leak with no other pathology on initial ERCP (OR, 6.74; 95% CI, 1.75-25.89) were independently associated with the absence of persistent bile leak and other pathology on repeat ERCP. The derived rule included laparoscopic cholecystectomy, normal postsurgical ALP, minor leak with no other pathology on initial ERCP, and an interval from initial to repeat ERCP between 4 and 8 weeks. When all 4 criteria were met, the rule had a sensitivity of 94% (95% CI, 83%-99%) and a negative predictive value of 93% (95% CI, 81%-99%). Optimism-adjusted sensitivity and negative predictive value were 88% (95% CI, 76%-96%) and 86% (95% CI, 73%-96%), respectively. This clinical decision rule identifies patients who can have their biliary stents removed via gastroscopy, which may improve patient safety and healthcare utilization.

Endoscopic intervention for persistent bile leakage after cholecystectomy

Endoscopic intervention for persistent bile leakage after cholecystectomy

Characteristics and treatments of spinal fractures associated with dural tears

Objective To investigate the characteristics and treatment effects in patients with spinal fractures associated with dural tears. Methods A retrospective analysis was made on 185 patients with spinal fractures presenting to hospital from February 2013 to February 2015. There were 103 males and 82 females, aged 17-73 years (mean, 58 years). Causes of injury were high falls in 72 patients , traffic collisions in 58, hitting by heavy objects in 41, ground-level falls in 12, and collision events in two. Cervical spine fractures were seen in 65 patients, thoracic vertebra fractures in 51, and lumbosacral vertebral fractures 69. Neurologic deficit was assessed using the American Spinal Injury Association (ASIA) score, including grade A in 24 patients, grade B in 22, grade C in 26, grade D in 37 and grade E in 76. Eighty patients were managed by simply anterior surgery, 97 by posterior surgery, and eight by anterior-posterior surgery. Twenty-one patients were found with dural tears (group A) and 164 patients without dural tears (group B). Incidence of dural tears in cervical, thoracic and lumbosacral vertebral fractures were recorded and compared. Preoperative neurologic deficit, laminar fracture and spinal canal encroachment rate were compared between groups. Neurological function and complications associated with dural repair were detected. Results In group A, ten patients were rated ASIA grade A, five grade B, three grade C, one grade D and two grade E. In group B, 14 patients were rated ASIA grade A, 17 grade B, 23 grade C, 36 grade D and 74 grade E. Group A accounted for 11%(7/65) of cervical, 10%(5/51) of thoracic, and 13%(9/69)of lumbosacral spine fractures (P>0.05). Nineteen patients (91%) in group A were complicated with neurological deficit, compared to ninety patients (54.9%) in group B (P<0.01). Eighteen patients (86%) in group A had laminar fractures, compared to fifteen patients (9.1%) in group B (P<0.01). In group A, rate of spinal canal encroachment was (62.3±12.1)% and 17 patients (81%) showed spinal canal encroachment of greater than 50%. While in group B, rate of spinal canal encroachment was (36.2±15.6)% and 25 patients (15.2%) showed spinal canal encroachment of greater than 50% (P<0.01). For dural tears in group A, 11 patients were treated by direct suturing, four by thoracolumbar fascia repair, three by artificial dural coverage and three by fibrin glue sealing. In group A, 19 patients were followed up and one of them presented persistent cerebral spinal fluid leak that necessitated an irrigation and debridement to cure. ASIA score was improved from grade A to B in two patients, grade B to C in one, grade C to D in one and grade D to E in one at the final follow-up. Conclusions Majority patients with spinal fractures associated with dural tears exist severe neurologic deficit, spinal canal encroachment and laminar fractures. Incidence of dural tear in cervical, thoracic and lumbosacral vertebral fractures is similar. Incidence of complications related to dural tear repair is low, but the neurological function recovery is poor after operation. Key words: Spinal fractures; Dura mater; Spinal cord injuries; Complications

Staged bilateral single-port thoracoscopic lung volume reduction surgery: A report of 11 cases.

The aim of the present study was to investigate the feasibility and efficacy of staged bilateral single-port thoracoscopic lung volume reduction surgery (LVRS) for patients with chronic obstructive pulmonary emphysema (COPE). Eleven male patients with a mean age of 60.27±12.11 years with bilateral COPE and bullae were admitted to the Department of Thoracic Surgery, Xuzhou Central Hospital from January 2013 to June 2014. The patients underwent staged bilateral single-port thoracoscopic LVRS. The hyperinflated bullae were resected using endoscopic staplers (Endo-GIA), followed by continuous suture and biological glue for reinforcement of the margin. In addition, pulmonary function, blood gas assay, 6-min walk distance (6MWD) and life quality evaluated by a short form 36-item health survey questionnaire (SF-36) were recorded before and after LVRS, respectively. All the patients survived after surgery. The chest tube drainage time was 9.09±1.31 days and postoperative hospital stay was 15.73±2.75 days, with 5 cases of persistent air leakage and 7 cases of pulmonary infection which were finally cured. The patients were followed up for 3 to 12 months, and the pulmonary function, partial pressure of oxygen (pO2), 6MWD and life quality after unilateral or bilateral LVRS were improved compared to these parameters before surgery. However, there was no significant difference between unilateral and bilateral LVRS in terms of life quality. In conclusion, staged bilateral single-port thoracoscopic LVRS may improve the short-term life quality of patients with COPE.

Early postoperative complications after middle lobe-preserving surgery for secondary lung cancer.

Preservation of the middle lobe during lung surgery is traditionally avoided, because its presence in the hemithoracic cavity is considered a cause of complications. We report a series of lung cancer patients who underwent a secondary pulmonary resection with the preservation of the middle lobe to explore the complications and feasibility of these procedures. We reviewed the clinical courses of six patients who underwent surgery for metachronous lung cancers. Five patients underwent right upper lobectomy, including one sleeve lobectomy, after having undergone prior right lower lobectomy. The remaining patient underwent a right lower lobectomy after having undergone a prior right upper lobectomy. There were no treatment-related deaths. One patient was readmitted for surgery to treat delayed air leakage progressing to pyothorax. One patient was treated for persistent air leakage. Two patients required intermittent drainage of pulmonary effusion, because of middle lobe atelectasis. The postoperative forced vital capacity and forced expiratory volume in 1s were greater than the values predicted post-pneumonectomy in four evaluable patients. While postoperative complications after middle lobe-preserving surgery are manageable, their high incidence should be considered when performing this surgery.

OCT‐A versus FA guided focal laser, in macular ischemic microangiopathies

SummaryThe clinically significant macular oedema, related to the macular microcirculation abnormal permeability, ischemic changes or aneurysmal changes, were identified during the evolution of the most common retinal ischemic micro‐angiopathies.Intravitreal anti‐VEGF or steroids demonstrated their efficacy to reverse the macular blood retinal barrier changes, resolving the characteristic oedematous macular changes leading to the observed clinically significant functional improvement.The confrontation of the OCT‐angiography monitoring of the superficial and deep capillaries plexus changes to the fluoresceine angiography observed persistent leaking capillaries segment or micro‐aneurysms, allows the applications precise focal laser treatment.Intravitreal anti‐VEGF associated to focal laser treatment results to superior functional results than intravitreal anti‐VEGF alone in late onset treated BRVO cases.

Concurrent use of endourological and radiologic methods in the management of high-grade renal trauma.

This case report explores the efficacy of simultaneous use of endourological and radiological methods to assess and manage high-grade renal trauma. A male rugby player was diagnosed with Grade 4 blunt renal trauma. A segment of the patient's kidney was isolated from the main renal pelvis with intact perfusion. This resulted in urinary extravasation. Ureteral stenting and angioembolization were used to treat the patient's severe symptoms. Angioembolization ablated functional tissue that was causing a persistent urinary leak. Following the treatment, the patient was discharged with no significant bleeding or leakage from the kidney. This report illustrates an uncommon use of this combined approach. Followup 18 months post-trauma revealed normal blood pressure and approximately 30% loss of volume of the affected kidney.