Influence of Optic and Haptic Materials on the Adherence of Staphylococcus Epidermidis to Intraocular Lenses: A Pilot Study

To evaluate in vitro the adherence of Staphylococcus epidermidis to intraocular lenses (IOL) of different optic and haptic materials and design, we used a quantitative cultural method. Polymethylmethacrylate (PMMA), PMMA-prolene, polyHEMA, silicone and surface-modified PMMA (wet and dry) implants were tested.

Adherence differed significantly in the various groups, with the best performance by all-PMMA IOL.

Staged laparoscopic-assisted endorectal pull-through for long segment Hirschprung's disease and total colonic aganglionosis

AIM

Recently laparoscopic endorectal pull-through (LERPT) has been widely performed for treatment of Hirschsprung's disease (HD) as a one stage procedure. In long segment aganglionosis (LSA) and in case of total colonic aganglionosis (TCA) a staged procedure can be preferred. The authors report their experience in the staged LERPT for LSA and TCA.

METHODS

In the last five years we treated 4 infants (3 male, 1 female) with LSA and TCA. The mean age at presentation was 40 days (2-110 days). In 3 patients we performed in the first step rectal biopsies, multiple laparoscopic biopsies and stoma. In one case ‑ presenting as small bowel obstruction - we performed an emergency laparotomy for ileostomy and biopsies of the bowel. Histology showed 2 left colon aganglionosis (LCA) and 2 TCA. The LERPT was performed at a main age of 10 months. After stoma closure the LERPT was performed according to Georgeson's technique.

RESULTS

There were no intraoperative complications. The patient with previous laparotomy needed conversion because of the abdominal adhesions. The two infants with LCA had preoperative and recurrent postoperative enterocolitis. In one case a successful posterior anorectal myectomy was performed. At follow up the children present constipation. The patient with TCA undergoing to LERPT presents a good frequency of defecation.

CONCLUSION

Our experience, although on limited series, shows that staged minimally invasive surgical treatment can be safely performed in the LSA and TCA, but conversion can be necessary especially in case of previous laparotomy.

Posterior urethral polyp causing haematuria in children

Posterior urethral hemangioma (PUH) is a rare congenital lesion, included in group of polypoid or papillary lesion of the prostatic urethra. This lesion is responsible for a variety of symptoms in children that may be associated or isolated, sometimes its finding is occasional. The diagnosis is usually made by ultrasonography and cystourethrogram, but the gold standard is represented by the urethrocystoscopy with double possibility: diagnostic and therapeutic. The Authors report a case of 1-year-old boy with persisting haematuria, in whom a previews cystoscopy didn't find any cause of haematuria. An accurate urethrocystoscopy let to make diagnosis of prostatic urethral polyp, a transurethral resection was performed and pathological assessment confirmed the diagnosis of PUH.

Diagnosis of Hirschsprung's Disease: an age-related approach in children below or above one year

AIM

The aim of this study was to evaluate the effectiveness of a differential diagnostic approach to Hirshchsprung's Disease (HD) on the basis of age.

METHOD

Data on 185 consecutive children with suspected HD were subjected to an age-related diagnostic approach. The patients were divided into two groups according to age (A < 1 year; B > 1 year). Children in Group A had rectal suction biopsy (RSB) and contrast enema (CE), and in Group B anorectal manometry (ARM) was performed. Patients with a normal recto-anal inhibitory reflex (RAIR) underwent bowel disimpaction and medical treatment. Only selected cases in Group B underwent RSB and CE.

RESULTS

In Group A (18 patients) CE showed a colonic transitional zone in three patients, whereas RSB led to the diagnosis of HD in nine. In Group B (167 patients) ARM was not possible in seven patients and it was normal in 140 (normal anal sphincter pressure: 83; hypertonia of the internal anal sphincter: 57). The RAIR was negative in 20 patients. RSB performed in 31 children in Group B confirmed HD in three patients.

CONCLUSIONS

For patients with a neonatal onset of constipation RSB is the best diagnostic technique. Chronic constipation is rarely due to HD and ARM is a useful non-invasive screening tool.

Role of anorectal manometry in children with severe constipation

OBJECTIVE

Constipation is one of the most frequent disorders of the digestive tract in children and it can be an important problem in paediatric and surgical practice. Most of the time, the cause is psychological or because of a slowing of colonic transit, but it can be a sign of organic gastrointestinal outlet obstruction. Some patients with chronic constipation are resistant to a medical approach and they present with a severe form of constipation that needs recurrent hospital admission. Anorectal manometry (ARM) is a noninvasive procedure and it helps to explain the mechanisms of defecation disorders. The aim of the present study was to evaluate the role of ARM in children with severe constipation.

METHOD

From October 2003 to October 2006, in the Paediatric Surgery Unit, 85 children - aged more than 1 year - with severe constipation were seen. The mean age was 5 years (range, 1-13). At presentation, every child had abdominal and rectal examination in order to identify abdominal distension or faecal masses. Bowel preparation with enemas was performed before ARM in patient with a rectal faecaloma. Myoelectric activity of the internal anal sphincter and resting anal tone was recorded; recto-anal inhibitory reflex (RAIR) was tested to exclude Hirschsprung's disease (HD). Anal tone was considered normal until 50 cm H(2)O. When the RAIR was absent, the patient underwent rectal suction biopsies (RSB) for histology and acetylcholinesterase histochemistry. In cases of normal or high anal tone with the RAIR present, the child had bowel cleaning, medical treatment, 2- and 6-month follow-up. Children with ineffective treatment at follow-up underwent RSB. In case of HD, a laparoscopic-assisted endorectal pull-through (ERPT) according to Georgeson's technique was performed.

RESULTS

Seventy per cent of the patients had bowel preparation before ARM. In four patients the ARM was impossible to assess because of crying. In 28 patients, the anal tone result was higher than 50 cm H(2)O and local treatment with anaesthetic agents was used for 8 weeks. Seventeen patients underwent RSB: 11 patients with RAIR absent/unclear, 4 noncooperative children and 2 patients with ineffective medical treatment at follow-up. HD was diagnosed in 2 patients and laparoscopic-assisted ERPT was performed. The remaining patients had good results at 6-month follow-up.

CONCLUSION

ARM is a noninvasive diagnostic tool to study the mechanism of defecation in children with constipation in order to prescribe the appropriate treatment. This procedure can be used in every child - aged more than 1 year - with severe constipation and assessment of the RAIR can select the cases for RSB.

One-trocar transumbilical laparoscopic-assisted management of Meckel's diverticulum in children

PURPOSE

Transumbilical laparoscopic-assisted intestinal surgery using only "one trocar" is a very minimal invasive procedure. The authors present their experience for the management of Meckel's diverticulum.

MATERIALS AND METHODS

Between January 2001 and December 2004, 9 transumbilical laparoscopic-assisted procedures were performed for Meckel's diverticulum. The median age of the patients was 6.1 years (range, 6 months-13.6 years). Six patients were admitted for intestinal bleeding and technetium-99m pertechnetate scan was positive in 3. Three patients had recurrent abdominal pain and abdominal ultrasound scan showed a cystlike structure. An intraumbilical Hasson 10-mm trocar was inserted in an open fashion. Using a 10-mm operative laparoscope, the terminal ileum was grasped with an atraumatic instrument and exteriorized through the umbilicus. Ileal exploration and treatment were performed extracorporeally.

RESULTS

Meckel's diverticulum was identified in 8 patients and ileal duplication in 1 patient: intestinal resection/anastomosis (n = 7) or excision of diverticulum (n = 2) was performed. There were no operative complications. Median hospital stay was 4 days (range, 3-7 days). At a median followup of 24 months (range, 3-51 months), all patients are asymptomatic.

CONCLUSION

Our results indicate that the one trocar transumbilical laparoscopic-assisted procedure is safe and effective for the diagnosis and treatment of Meckel's diverticulum, with excellent cosmetic results.

Neonatal adrenal hemorrhage presenting as contralateral scrotal ematoma

Neonatal adrenal hemorrhage may rarely present as scrotal hematoma. This condition can simulate a torsion of the testis requiring an immediate surgical exploration of the scrotum. Ultrasonographic study of the abdomen can find out intraperitoneal or retroperitoneal bleeding in order to avoid unnecessary surgical intervention. The case of a newborn with right adrenal hemorrhage presenting as left scrotal hematoma is reported.

[Antimicrobial agents for preventing peritonitis in peritoneal dialysis: guideline from the Italian Society of Nephrology]

BACKGROUND

The current 3rd edition of the Italian Society of Nephrology guidelines has been drawn up to summarize evidence of key intervention issues on the basis of systematic reviews (SR) of randomized trials (RCT) or RCT data only. The present guideline reports evidence of the use of antimicrobial agents for preventing peritonitis in peritoneal dialysis (PD).

METHODS

SR of RCT and RCT on treatments aiming at preventing peritoneal dialysis peritonitis were identified referring to a Cochrane Library and Renal Health Library search (2005 update). Quality of SR and RCT was assessed according to current methodological standards.

RESULTS

One SR and 19 RCT were found addressing this issue. Staphylococcus Aureus nasal carriage treatment with mupirocin reduces exit-site and tunnel infections but not peritonitis. Topical gentamicin treatment on the exit site reduces Staphylococcus Aureus infection and peritonitis incidence. Intravenous antibiotics administration prior to catheter placement significantly reduces the risk of early peritonitis but not exit-site and tunnel infections. Oral nistatin associated with antibiotic treatment significantly reduces the incidence of Candida peritonitis. No other prophylaxis measure seems to be effective based on available evidence.

CONCLUSION

In patients on peritoneal dialysis current evidence supports the hypothesis that topical mupirocin reduces the risk of Staphylococcus Aureus peritonitis, intravenous antibiotics prior to catheter placement prevent the risk of early peritonitis, and oral nistatin reduces the risk of Candida peritonitis. Further studies are necessary to test the effectiveness of other interventions.

Laparoscopic Fowler-Stephens procedure is contraindicated for intraabdominal testicular major duct anomalies

The laparoscopic one- and two-stage Fowler-Stephens procedure has gained large popularity in the treatment of the child with a high intraabdominal testis. It is largely debated which technique (e.g., testicular autotransplant or Fowler-Stephens procedure) offers the best results for high intraabdominal testes. We describe a case of a 3-year-old boy for whom previous bilateral inguinal exploration results were negative for testes or testicular remnants. The diagnostic laparoscopy showed two iliac intraabdominal testes with short spermatic vessels, closed inguinal rings, and complete dissociation of didime-epididime. A left open orchidopexy was perfomed, and testicular autotransplant was proposed for the right testes located 4 cm from the internal inguinal ring. Long-term follow-up evaluation (1.8 years) of the left testis showed it in the scrotum with good testicular size (1.5 cm). We believe that there are two main reasons to contraindicate the Fowler-Stephens technique: associated malformation that does not permit the development of the collateral blood flow via the vasal artery necessary for a viable testis, and previous surgery that represents a risk factor for testicular atrophy. The laparoscopic anatomic classification for the intraabdominal testis is reliable and can disclose the most suitable surgical technique. Laparoscopy is a valuable tool in the diagnosis and treatment of the nonpalpable testicle.

Detection of crossing vessels at the ureteropelvic junction with fast MRI

OBJECTIVE

Minimally invasive surgery is an alternative to open surgery in the treatment of ureteropelvic junction obstruction (UPJO) in selected pediatric patients. Anomalous crossing vessels represent a contraindication to endopyelotomy and may also interfere with the videosurgical pyeloplasty. We investigated the usefulness of magnetic resonance imaging (MRI) without contrast in the preoperative evaluation of anomalous crossing vessels in children.

MATERIALS AND METHODS

From January 1999 to December 1999, 14 patients with diagnosis of hydronephrosis were prospectively evaluated with the aim of accurately plan the operative approach. The children underwent MRI study with HASTE sequences, heavily T2 weighted. Diagnosis was made without IV contrast material. No sedation was used.

RESULTS

4 out of the 14 patients studied were diagnosed as having anomalous crossing vessels at the ureteropelvic junction. They underwent open dismembered pyeloplasty and the diagnosis was confirmed at the operation. There was 1 false negative.

CONCLUSIONS

The fast T2 weighted MRI allows a non invasive preoperative assessment of crossing vessels at the UPJO which is of paramount importance in the choice of the appropriate surgical approach. Nevertheless, the high cost and the low sensitivity (80%, 4/5) make this technique still not routinely applicable in the preoperative work-up of children with UPJO.

Italian multicenter survey on laparoscopic treatment of gastro-esophageal reflux disease in children

BACKGROUND

Skepticism is still present today about the laparoscopic treatment of gastro-esophageal reflux (GER) in children. We present the prospective experience and short-term results of eight Italian pediatric surgical units.

METHODS

We included all the children with complicated GER, operated after January 1998 by single surgeons from eight different centers. Diagnostic aspects, type of fundoplication, and complications were considered. All the patients were followed for a minimum period of 6 months in order to detect complications or recurrences.

RESULTS

288 children were prospectively included. Mean age was 4.8 years (3 m-14 y). Nissen fundoplication was done in 25%, floppy Nissen in 63%, Toupet in 1.7%, and anterior procedures (Lortat Jacob, Thal) in 10%. Gastrostomy was associated, if neurological impairment or feeding disorders were present. Mean follow-up was 15 months and reoperation was necessary in 3.8% of cases.

CONCLUSIONS

This experience underlines that minimal invasive access surgery in children is safe and that the laparoscopic approach is considered in eight centers the golden standard for surgical repair of gastro-esophageal reflux disease maintaining the same indications and techniques of the open approach.

Hyperinsulinism reduction associated with icodextrin treatment in continuous ambulatory peritoneal dialysis patients

Glucose absorption from peritoneal dialysis solutions causes a chronic stimulation of insulin secretion, which leads to hyperinsulinism. The use of solutions without glucose should correct this metabolic derangement together with the associated cardiovascular risk. To verify this hypothesis, we studied the entire non diabetic continuous ambulatory peritoneal dialysis (CAPD) population of our center: 27 patients with a mean age of 62 +/- 15 years, and a median 17 months on treatment. Morning fasting serum insulin was 32.8 +/- 9.3 microU/mL; glucose, 104.4 +/- 21.8 mg/dL; triglycerides, 162.4 +/- 125.7 mg/dL; cholesterol, 221.9 +/- 54.7 mg/dL; intact parathyroid hormone (iPTH), 212 +/- 189 pg/mL; fibrinogen, 519 +/- 112 mg/dL; body mass index, 24.1 +/- 4.1; and daily erythropoietin subcutaneous therapy dose, 17 +/- 6 U/kg. Insulin sensitivity, measured as ISI-HOMA (insulin sensitivity index, derived from the homeostasis model assessment) was 2.4 +/- 0.7. Daily glucose load, calculated from dialytic schedules, was 135 +/- 38 g. Of the 27 patients, 12 were treated with standard glucose solutions during the day and with one icodextrin dwell during the night for a median of 9 months (range: 1-28). The remaining 15 patients were treated with standard glucose solutions. The icodextrin group showed significantly lower serum insulin levels (28.6 +/- 6.0 microU/mL vs 36.1 +/- 10.2 microU/mL, p = 0.021) and significantly higher ISI-HOMA values (2.7 +/- 0.5 vs 2.2 +/- 0.7, p = 0.041) than the control group. The two groups showed no significant differences for glucose, triglycerides, cholesterol, iPTH, fibrinogen, body mass index, or erythropoietin therapy dose. Daily glucose load was lower in the icodextrin group, but without reaching statistical significance (128 +/- 31 g vs 142 +/- 43 g). This study shows, in a preliminary way, that the chronic use of icodextrin in the long nighttime dwell can reduce serum insulin levels and increase insulin sensitivity in CAPD patients.

Unusual clinical presentation of a rare case of phyllodes tumor of the breast in an adolescent girl

Phyllodes tumor of the breast is a very rare neoplasm, particularly in adolescent girls and young women. It usually presents as unilateral palpable mass. The authors report the case of an adolescent girl who presented at the Emergency Department with bloody nipple discharge. Although the clinical signs suggested an intraductal tumor, the histologic examination showed a phyllodes tumor. The management and the biologic behavior of this uncommon tumor are discussed with particular regard to the very unusual clinical presentation in this patient. J Pediatr Surg 36:941-943.

One-trocar surgery: a less invasive videosurgical approach in childhood

BACKGROUND/PURPOSE

Laparoscopic techniques and instruments are evolving to lessen the invasiveness of this surgical approach. The authors present their experience with the videosurgical approach using only 1 trocar.

METHODS

Between October 1997 and January 2000 the authors performed 59 videosurgical procedures using a 1-trocar approach (mean age, 11.5 years; range, 4 to 18 years). A 10-mm Hasson trocar was inserted in an "open" fashion either through the umbilicus (laparoscopy) or below the apex of the 12th rib (retroperitoneoscopy). An operative laparoscope was used in all cases. The operations were 18 retroperitoneoscopic Palomo varicocelectomies, 1 retroperitoneoscopic renal biopsy, 38 appendectomies, and 2 ileal resections (Meckel's diverticulum, duplication cyst). For appendectomies and ileal resections, the corresponding intestinal loop was grasped and exteriorized through the umbilicus to perform conventional surgery.

RESULTS

Mean operating time was 50.9 minutes (range, 30 to 120) for laparoscopies and 44 minutes (range, 15 to 80) for retroperitoneoscopy. There were 11 conversions (8 appendectomies, 3 varicocelectomies) and no postoperative complications.

CONCLUSIONS

"One-trocar surgery" is safe, effective, and fast with a low complication rate and excellent cosmetic results. The authors believe it is the least invasive as well as the most effective approach in the treatment of varicocele, appendicitis, and selected intestinal diseases.

Results and complications of laparoscopic surgery for pediatric varicocele

BACKGROUND

The aim of this study was to evaluate the results and complications of laparoscopic varicocelectomy in children.

METHODS

Over a 36-month period, 211 children underwent laparoscopic treatment of varicocele. Their ages ranged between 6 and 17 years; the varicocele was located on the left side in 209 cases (99.1%) and was bilateral in 2 (0.9%). In 195 patients the laparoscopic transperitoneal approach was used and in 16 retroperitoneoscopy was used. Thirty children (14.2%) underwent ligation of the veins alone, and 181 (85.8%) underwent ligation of testicular veins and artery. In 15 (7.1%) cases an additional procedure was applied during the same operation.

RESULTS

Average operating time was 30 minutes and hospitalization about 24 hours. At an average follow-up of 26 months, there were 19 (9%) postoperative complications: 14 children had a left hydrocele, 3 children a scrotal emphysema, and 2 an umbilical granuloma. There were 5 recurrences of varicocele in our series: 2 (2 of 30, 6.6%) after the Ivanissevitch procedure, and 3 (3 of 181, 1.6%) after Palomo's. Testicular atrophy did not occur in any patient of this series.

CONCLUSIONS

This preliminary experience shows that the results of the laparoscopic approach are comparable to those of the open approach. The ligation of testicular veins and artery is preferable to the ligation of the testicular veins alone. Hydrocele seems to be the most frequent postoperative complication and a potential problem, especially in children operated on with the Palomo procedure.

Complications of laparoscopic antireflux surgery in childhood

BACKGROUND

The aim of this study was to assess the complications associated with the laparoscopic treatment of gastroesophageal reflux disease (GERD) in children.

METHODS

From March 1992 to March 1998, we used the laparoscopic approach to treat 289 children affected by gastroesophageal reflux disease. The patients' ages ranged between 4 months and 17 years (median, 4.3 years), and their body weight ranged between 5 and 52 kg. In 148 children (51.3%), we adopted a Nissen-Rossetti procedure and in 141 (48.7%) a Toupet technique.

RESULTS

The duration of surgery ranged between 40 and 180 min (median, 70). There were no deaths and no anesthesiological complications in our series. We recorded 15 (5.1%) intraoperative complications: six pleural perforations, four lesions of the posterior vagus nerve, two esophageal perforations, two gastric perforations, and one pericardiac perforation. Conversion to open surgery was necessary in only four cases (1.3%). We recorded 10 (3.4%) postoperative complications: one peritonitis due to an esophageal perforation not detected during the intervention that required a reoperation, five cases of herniation of the epiploon through a trocar orifice, three cases of dysphagia that disappeared spontaneously after a few months, and one case of delayed gastric emptying that subsequently required a pyloroplasty. We had six recurrences of GERD (2.1%). In two cases, a new fundoplication was performed using the laparoscopic approach; in the other four, the GERD was controlled with medical therapy.

CONCLUSION

Our results show that laparoscopic fundoplication is an adequate treatment for children with GERD that has a low rate of complications. When severe complications do occur, they can be treated effectively via the laparoscopic approach.

Laparoscopic orchiopexy without division of the spermatic vessels: can it be considered the procedure of choice in cases of intraabdominal testis?

BACKGROUND

Several surgical procedures have been described for the management of nonpalpable testis. Following a vast experience with a complete laparoscopic two-stage Fowler-Stephens procedure, we report our experience with laparoscopic orchiopexy performed without dividing the spermatic vessels.

METHODS

Over a 24-month period, 70 boys with nonpalpable testes (72 overall) underwent laparoscopic diagnostic exploration. Twenty patients (27.8%) of this series who showed an intraabdominal testis underwent laparoscopic orchiopexy without sectioning the spermatic vessels. In seven cases, the testis was just proximal to the internal inguinal ring; in 13, it was in the high intraabdominal position. The technique consisted in sectioning the gubernaculum (when present), opening the peritoneum laterally to the spermatic vessels, and mobilizing the testicular vessels and the vas deferens in a retroperitoneal position for 8-10 cm. The testis was then brought down into the scrotum through the internal inguinal ring (11 cases), if this was open, or through a neo-inguinal ring (nine cases) created medially to the epigastric vessels. In every case, we closed the inguinal ring at the end of the operation using one or two detached sutures.

RESULTS

Operating time ranged between 40 and 75 min (median, 55). All the testes were successfully brought down into the scrotum. We had only one (5%) intraoperative complication. In the second patient treated with this procedure, there was an iatrogenic rupture of the spermatic vessels due to excessive traction.

CONCLUSION

On the basis of our experience, we believe that laparoscopic orchiopexy without division of the spermatic vessels should be the treatment of choice in the management of nonpalpable testes, because it does not affect normal testicular vascularization and is minimally invasive. A blunt dissection and a delicate manipulation of the testis without excessive traction are the best ways to avoid any kind of complication.

Laparoscopic treatment of pediatric varicocele: a multicenter study of the italian society of video surgery in infancy

PURPOSE

We report preliminary results of a multicenter study of the Italian Society of Video Surgery in Infancy on the laparoscopic treatment of pediatric varicocele.

MATERIALS AND METHODS

A total of 161 children 6 to 16 years old (median age 12.5) underwent laparoscopic treatment of varicocele at 6 pediatric surgery divisions. Varicocele was on the left side in 159 cases (98.7%) and bilateral in 2 (1.3%). Two boys had recurrent left varicocele. All children were treated with laparoscopy, including ligation of the spermatic veins only in 28 (17.3%), and ligation of the testicular veins and artery in 133 (82.7%). In 10 boys (6.2%) an additional procedure was done simultaneously, including closure of an apparently patent peritoneal vaginal duct on the right side in 7 and resection of epiploic adhesions between the intestinal loops and abdominal wall from previous appendectomy in the remaining 3.

RESULTS

Average operative time was 30 minutes and hospitalization was about 24 hours. At followup there were 13 minor complications (8%), including left hydrocele in 9 children who underwent the Palomo technique, minor scrotal emphysema in 2 and umbilical granuloma in 2. In our series varicocele recurred in 1 boy (3.5%) who underwent ligation of the spermatic veins only and in 3 (2.2%) treated with the Palomo technique.

CONCLUSIONS

Our preliminary experience shows that the results of the laparoscopic approach are comparable to those of the open approach. However, the important advantages of laparoscopy over the open approach are its minimal invasiveness and precision of intervention. Moreover, laparoscopy allows treatment of other intra-abdominal pathological conditions using the same anesthesia, as in 10 patients in our series. We believe that ligating the testicular veins and artery is preferable to ligating the testicular veins only, even if the incidence of hydrocele is not negligible after the Palomo procedure.

Complications of laparoscopic treatment of esophageal achalasia in children

BACKGROUND/PURPOSE

The aim of this study was to evaluate the incidence and management of the complications that occurred in some children who underwent laparoscopic Heller's esophagocardiomyotomy in the authors' institutions.

METHODS

Between March 1993 and October 1998, the files of all the children with achalasia who underwent laparoscopic Heller's esophagocardiomyotomy in a community hospital in Naples, Italy, and a private hospital in Paris, France, were reviewed. A 5-port technique was used associating Heller's esophagocardiomyotomy to an antireflux surgical mechanism (Dor's or Toupet's) in all cases. Intra- and postoperative complications, as well as the postoperative outcome, were evaluated.

RESULTS

Ten laparoscopic Heller's esophagocardiomyotomies were performed in 5 girls and 5 boys with achalasia. Age ranged between 2 and 13 years. Mean operating time was 120 minutes. Hospital stay ranged between 3 and 41 days. Complications were recorded in 3 patients: in 2 an esophageal mucosal perforation and in 1 a prolonged dysphagia. Two of these complications occurred in the last patients operated on. Follow-up varied from 6 months to 6 years. All children were free of symptoms.

CONCLUSIONS

The results show that laparoscopic Heller's esophagocardiomyotomy in children is a feasible procedure. Assessment of mucosal integrity immediately after the myotomy must be performed. Complications can happen even if the operation is performed by expert laparoscopic surgeons.

Continuous tidal peritoneal dialysis (CTPD) prescription and adequacy targets

NKF-DOQI guidelines suggest a Kt/V value of 2.1 and a creatinine clearance (CRCL) value of 63 L/1.73 m2 of body surface area per week as minimum targets in continuous cycling peritoneal dialysis (CCPD). Those targets are obtained by adapting the CAPD guidelines. The aim of our study was to verify the possibility of reaching the suggested targets with continuous tidal peritoneal dialysis (CTPD) and to check target modification in this automated treatment. Eight anuric patients underwent four consecutive CTPD sessions with increasing total prescribed volumes (17 L, 22 L, 27 L, and 32 L; night 9 h; fill 2.2 L; tidal 75%, day 2 dwells). The Kt/V increase was significant (P = 0.012), unlike that of CRCL, with larger volumes. Two patients did not reach target Kt/V, and four did not reach target CRCL. The volume normalized for 1.73 m2 corresponding to DOQI targets was 19.6 +/- 2.6 L for Kt/V and 20.2 +/- 2.4 for CRCL. The overall Kt/V was 2.29 +/- 0.66 and CRCL was 57.3 +/- 16.5 L/1.73 m2. CRCL/Kt/V overall ratio was 25.6 +/- 4.7 and significantly different from the target ratio (63/2.1 = 30, P < 0.001). The CRCL/Kt/V ratio showed a significant decrease with larger volumes (P = 0.001, linear trend P < 0.001). Adequacy targets can be reached only in some patients on CTPD even with high dialysis volumes. The changes in the CRCL/Kt/V ratio in relation to dialysis volume can be considered for adaptation and evaluation of adequacy targets in automated treatments.

Day-to-day variability of adequacy indexes in peritoneal dialysis

BACKGROUND

The achievement of dialysis adequacy targets in peritoneal dialysis (PD) is assessed by the calculation of the Kt/V and creatinine clearance (C(Cr)) obtained by collecting dialysate and urine, usually two or three times a year. Prescription decisions are based on such adequacy assessments, regardless of any variability in the single measurements. The aim of our study was to assess the day-to-day variability of common dialysis adequacy parameters and to evaluate its impact on the adequacy indexes in PD.

METHODS

Twenty-four patients (14 CAPD, 10 APD) at two centres were studied by means of a triple dialysate and urine collection for a period of 1 week. Variability in the findings for a given patient was expressed by the coefficient of variation (CV%) calculated for peritoneal (p), renal, and total (tot) adequacy parameters. The target Kt/V and C(Cr) values were recalculated on the basis of variability.

RESULTS

Kt/V was less variable (CV 4.0 and 4.4% for peritoneal Kt/V (pKt/V) and total Kt/V (totKt/V) respectively) than C(Cr) (4.7 and 6.0% for peritoneal creatinine clearance (pC(Cr)) and total creatinine clearance (totC(Cr)) respectively) and proved to be a more reliable indicator of adequacy in terms of the CV. Both variability parameters became worse if renal clearance was added to peritoneal clearance. CV in APD proved to be no different from CAPD for all the parameters considered. In our centres dialysis adequacy target correction for variability provided safe values for weekly Kt/V (pKt/V=1.78-2.10 and totKt/V=1.82-2.15 target 1.7-2.0) and C(Cr)/1.73 (pC(Cr)=53.7-64.4 l and totC(Cr)=55.1-66.1 l; target 50-60 l).

CONCLUSIONS

Evaluating the adequacy of PD by means of a single measurement should take into account the weekly variability as demonstrated by a triple dialysate and urine collection. Standard adequacy targets can be corrected to allow for variability. Thus one can obtain safe values for prescription decisions based on a single collection result.

Symptoms in hemodialysis patients and their relationship with biochemical and demographic parameters

Symptoms can markedly influence the hemodialysis patients well-being and quality of life. The aim of this paper is to study the frequency of symptoms at home and how these relate to biochemical and treatment variables. Seventy-three hemodialysis patients were questioned on the absence, occasional presence or daily recurrence (score = 0, 1, 2) of 14 symptoms and a record was made of their biochemical parameters, age, time on treatment and KtIV as a function of each symptom. The following relationships were detected: thirst with high Osm and BUN; asthenia with old age and hypoalbuminemia; insomnia with hypercalcemia; hypersomnia with hypoxemia and hypernatremia; anorexia with hypokalemia; dyspnea with old age, hypernatremia and hypokalemia; dysgeusia with hypoxemia; nausea with alkalemia, hypoxemia and low BUN; vomiting with alkalemia. Pruritus, arthralgia, restless legs syndrome, cramp and tremor showed no relationships. Monitoring acid-base balance and plasma electrolytes could help to alleviate symptoms and ameliorate quality of life of hemodialysis patients.

Optimal design of a two-sample test for assessing [125I]iothalamate plasma clearance in peritoneal dialysis

BACKGROUND

Plasma clearance of a tracer in peritoneal dialysis (PD) can be used to assess treatment adequacy without labour-intensive fluid collections. Accuracy and precision of plasma clearance estimates by the bolus injection technique depend on the estimation accuracy of the area under the concentration curve and the measurement precision of plasma concentrations. The first source of error is due to oversimplified, e.g. monoexponential, descriptions of plasma disappearance curves. The second source of error arises from the propagation of measurement errors to the parameter estimates.

METHODS

The theoretical bias of parameter estimates is determined first for a monoexponential approximation of a biexponential disappearance curve and as a function of the first sampling time at which mixing is still incomplete. The precision of plasma clearance estimates, expressed as coefficient of variation, is then described as a function of the experimental variables and of the standard deviation of measurement error. This allows the determination of the optimal two-sample test that yields most precise estimates of plasma clearance.

RESULTS

The optimal two-sample schedules for assessing plasma clearance of [125I]iothalamate in PD patients vary between subjects according to individual clearances and distribution volumes. Our results suggest collecting the first sample 120 min, and the second 2-4 days, after the bolus injection.

CONCLUSIONS

The proposed two-sample test is suitable to be used in clinical routine for assessment of adequacy of PD treatment but requires a priori estimation of individual tracer kinetics and of laboratory measurement errors. A fixed design with the first sample taken after 120 min and the second sample collected 3 days after the bolus injection should yield the best performance.

Clinical validation of PD Adequest software: modeling error assessment

OBJECTIVE

PD ADEQUEST software (Baxter Healthcare, Deerfield, IL, U.S.A.) is used in peritoneal dialysis for calculating the indices of dialysis efficiency and for the mathematical simulation of the results of various dialysis regimens. The aim of our study was to quantify the modeling errors and find the methods which give best results.

DESIGN

Nonrandomized, repeated measurement, clinical validation study.

PATIENTS

The study included 78 patients on continuous ambulatory peritoneal dialysis (PD), daytime ambulatory PD, and automated PD.

MEASUREMENTS

We used 207 collections of dialysate and urine associated with peritoneal equilibration tests (PETs) performed with different glucose concentrations (1.36%, 2.27%, 3.86%). The measured urea Kt/V, creatinine clearance (CRCL) and ultrafiltration (UF) were compared with the same data simulated mathematically using the PD ADEQUEST software version 1.4.

RESULTS

The Kt/V, CRCL, and UF measured values were significantly correlated and in agreement with modeled data [concordance correlation (rc) was 0.849, 0.839, 0.625 respectively]. The errors (modeled - measured) were: Kt/V = -0.04 +/- 0.27 (p = ns), CRCL = 2.1 +/- 7.7 L (p < 0.001), UF = -121 +/- 711 mL (p = 0.016). Applying ANOVA to both the peritoneal transport data calculated by PD ADEQUEST (mass transfer area coefficient of the solutes, fluid reabsorption, and hydraulic permeability) and the modeling errors, significant differences were found in relation to the PET glucose concentrations.

CONCLUSION

PD ADEQUEST proves to be a useful instrument in peritoneal dialysis, although there is undoubtedly still room for improvement in its prediction efficacy, which is influenced by the glucose concentration used in the PET.

The use of the PD Adequest mathematical model in pediatric patients on chronic peritoneal dialysis

OBJECTIVE

To test the accuracy of the PD ADEQUEST kinetic model in calculating peritoneal transport parameters and to quantify the differences between the results of software simulations and direct measurements in order to assess the reliability of this tool in chronic peritoneal dialysis (PD) pediatric patients.

PATIENTS

Twenty-nine patients (mean age: 10 +/- 4 years; range: 4-17), 5 on continuous ambulatory PD, 4 on continuous cycling PD, 19 on nocturnal intermittent PD and 1 in nocturnal tidal PD, all free from peritonitis in the previous 2 months. Fourteen patients were anuric and 15 had a mean glomerular filtration rate of 1.79 +/- 1.23 mL/min, range 0.25-4.82.

METHODS

In all patients, 24-hour dialysate and urine collections associated to standard peritoneal equilibration test (PET) were performed using their usual dialytic regimen and fill volume (1023 +/- 159 mL/m2 BSA, range 614-1361). PD ADEQUEST kinetic parameters were compared with pediatric and adult data from literature. The measured weekly normalized total creatinine clearance (CRCL), weekly total Kt/V, and daily net ultrafiltration (UF) were compared with corresponding mathematically modeled values.

RESULTS

Kinetic parameters calculated by the PD ADEQUEST program were comparable to adult and pediatric values from previous studies after normalization for BSA. Measured and modeled CRCL and Kt/V showed a good agreement [concordance correlation (rc) 0.937 and 0.768, respectively] with limited median percentage absolute errors (11.6% and 10.2%, respectively). Ultrafiltration showed less favorable results (rc = 0.600 and median percentage absolute error 45%) probably owing to the wide variability of this parameter. When the analysis was restricted to the peritoneal component, the rc coefficients results were 0.745 for CRCL and 0.512 for Kt/V (median absolute error: 11.6% and 15.2%, respectively).

CONCLUSIONS

The overall findings of our study show that the PD ADEQUEST kinetic model can be used in pediatric patients for the calculation of kinetic indexes and for mathematical simulation of the various regimens. We also feel that the results yielded by the PD ADEQUEST program are reliable enough for this computerized mathematical model to be used in the prescription management of pediatric patients. Only UF prediction needs to be used with a certain caution on account of the marked variability of this parameter.

Evaluation of Non-Linear and Linear Mathematical Models for Creatinine and Glucose Fitting in Peritoneal Dialysis

Four non-linear and five linear models for predicting the creatinine dialysate/plasma ratio (CRD/P) and the glucose dialysate/initial concentration ratio (GLD/Do) were evaluated in a group of 31 patients on peritoneal dialysis and subjected to the peritoneal equilibration test (PET 3.86%, 240'). PET results and classification were compared to obtain a definition of patient peritoneal transport characteristics. The monomolecular and rectangular hyperbola non-linear models, the Lineweaver-Burk, Hanes-Woolf and Dadone linear transformations were considered for the CRD/P fitting. A monoexponential and two-exponential decay plus the semilogarithmic transformations were considered for the GLD/Do. These models are simple, accurate and functionally homogeneous. Further studies are advisable however on the individual peritoneal transport classification, since ∼30% of the patients were in different categories for CRD/P and GLD/Do and the fittings do not give better classification results.

Evaluation of non-linear and linear mathematical models for creatinine and glucose fitting in peritoneal dialysis

Four non-linear and five linear models for predicting the creatinine dialysate/ plasma ratio (CRD/P) and the glucose dialysate/initial concentration ratio (GLD/D0) were evaluated in a group of 31 patients on peritoneal dialysis and subjected to the peritoneal equilibration test (PET 3.86%, 240'). PET results and classification were compared to obtain a definition of patient peritoneal transport characteristics. The monomolecular and rectangular hyperbola non-linear models, the Lineweaver-Burk, Hanes-Woolf and Dadone linear transformations were considered for the CRD/P fitting. A monoexponential and two-exponential decay plus the semilogarithmic transformations were considered for the GLD/ D0. These models are simple, accurate and functionally homogeneous. Further studies are advisable however on the individual peritoneal transport classification, since approximately 30% of the patients were in different categories for CRD/P and GLD/D0 and the fittings do not give better classification results.

Calcium lactate interference in measuring creatinine in peritoneal dialysis fluids by the Jaffé kinetic method

Creatinine measurements in peritoneal dialysis fluids using the Jaffé method have poor specificity due to interfering substances. We have checked to see if calcium lactate, in addition to glucose, interferes with the Jaffé kinetic measurement. Eight samples were prepared with increasing concentrations of glucose (960-3890 mg/dL) and eight were prepared with the same glucose content plus 7 mg/dL of calcium lactate, all without creatinine; in addition, 96 samples with increasing concentrations of glucose (1500-4000 mg/dL), calcium lactate (3-7.5 mg/dL), and creatinine (0.75-4.5 mg/dL) were prepared. There was a 0.31 +/- 0.13 mg/dL glucose interference on the Jaffé kinetic measurement in the first series, with an exponential trend. Interference was greater with calcium lactate and glucose: 0.50 +/- 0.16 mg/dL with the same trend. Data from the second series confirm the overestimation: 0.54 +/- 0.05 mg/dL (32.6%) with an exponential trend. The interference of glucose, creatinine, and calcium lactate on the Jaffé kinetic measurement was obtained by multi-variate regression. The single effects of glucose2 and glucose are predominant, but both creatinine and calcium lactate have a significant effect. Our study highlights the nonlinear glucose interference on creatinine measurement with the Jaffé kinetic method and the linear interference of both calcium lactate and creatinine.

Importance of donor/recipient body weight ratio as a cause of kidney graft loss in the short to medium term

The importance of the donor/recipient body weight ratio (DRBWR) as a cause of kidney graft loss was evaluated in 112 non-diabetic, ciclosporin-treated, first cadaver kidney transplant recipients. According to the DRBWR, the patients were divided into three groups: 'low' (< or = 0.80), 'medium' (0.81-1.20), and 'high' (> 1.20). The three groups did not differ in patient or graft survival, and the DRBWR was not a predictor of graft failure at multivariate analysis (Cox models), even after only patients with graft survivals > 1 year were considered. The three groups did not differ in glomerular filtration rate (GFR) and proteinuria 6-60 months after renal transplantation. When the 55 patients with a follow-up period > 4 years were considered, no differences between groups were found in GFR or GFR evolution over time. Hypertension was significantly less frequent in group 'high' (Mantel-Cox p = 0.04), but very likely as a consequence of uneven recipient gender (an independent predictor of hypertension at multivariate analysis) distribution between groups, the significance being lost when survival curves were rebuilt by stratifying for recipient gender. DRBWR never resulted as a significant predictor of GFR at multivariate analysis when GFR values 6-60 months after transplantation were analyzed. We conclude that the DRBWR has no major effects on kidney graft function and survival in the short to medium term.

Correction of glucose concentration interference on Jaffé kinetic creatinine assay in peritoneal dialysis

Overestimation of creatinine measurement using the Jaffé kinetic method in peritoneal dialysis solutions, due to glucose interference, has been quantified and corrected through the elaboration of linear formulas obtained from 110 recovery and 301 biological tests. The added pure powdered creatinine and enzymatic method were considered as references after proven accuracy. Considering creatinine as well as glucose concentration interference, we obtained correction formulas from multiple regression application. All the computed formulas gave satisfactory corrections but different accuracy levels. The best model in biological samples was: Corrected CR = K1JafféCr + K2Glucose (all values in mg/dl) where K1 = 0.973 and K2 = -0.00035 (Rsq = 0.987, F ratio = 10,945, p = 0.00001). Applying formulas to biological samples there was a drop in accuracy, possibly explained by the presence of numerous unidentified substances in peritoneal dialysis biological samples that can amplify scatter. Every laboratory can reduce the error of the Jaffé kinetic assay by calculating their own correction formula in relation to the method and instrument used, because Jaffé kinetic assay gives different results with different kinetic windows. So, especially when applied to peritoneal dialysis fluid measurements, if a creatinine assay reference method is not available, the correction formula can be applied directly as given. Otherwise the method we have described can be followed with a well-structured creatinine recovery fest to identify and quantify assay interferences.

Peritoneal dialysis prescription: the “Clearance Peak” model

Creatinine clearance (CRCL) was studied in 20 patients on CAPD in relation to the dwell times (DT), in order to establish a personalised dialysis schedule with the best clearance (CL) results, while respecting the patient's life-style. By calculating the CRCL from the two exchanges with dwell-times of 4 and 8 hours (2 1, 2.27%), curves (2nd degree polynomial regression) were plotted with three points (Oh, 4h, 8h) for CRCL and the ultrafiltration rate (UF) as a function of the DT. The DT corresponding to the CRCL peak (CLPeak-time) was calculated for each subject with the first derivative of the function. On the basis of the CRCL obtained with the three most common DT (4h, 6h, 8h), we divided the patients into three categories (CLPeak-time <5h: “fast”, 5-7h: “normal”; >7h: “slow”) for the best CRCL correspondence of the 4h, 6h or 8h exchanges respectively. Also the 8h/4h ratio was used to determine CLPeak-time. For each of the three categories there is a corresponding dialysis schedule for the best CRCL and UF results of the exchanges with DT of 4, 6 and 8 hours, plus the theoretical calculation of the daily CRCL obtainable (“fast”: APD; “normal”: CAPD 4 exchanges/DAPD 4 exchanges; “slow”: CAPD 4 exchanges). The “CLPeak” dialysis prescription model therefore identifies the most advantageous DT for each patient by using the CRCL values of two 2.27% exchanges of 4 and 8h respectively. Functional classification into three categories may give a rational orientation to dialysis prescription in order to reach the maximum CRCL possible with the individual peritoneal transport rates.

Peritoneal dialysis prescription: the "Clearance Peak" model

Creatinine clearance (CRCL) was studied in 20 patients on CAPD in relation to the dwell times (DT), in order to establish a personalised dialysis schedule with the best clearance (CL) results, while respecting the patient's life-style. By calculating the CRCL from the two exchanges with dwell-times of 4 and 8 hours (2 I, 2.27%), curves (2nd degree polynomial regression) were plotted with three points (0h, 4h, 8h) for CRCL and the ultrafiltration rate (UF) as a function of the DT. The DT corresponding to the CRCL peak (CLPeak-time) was calculated for each subject with the first derivative of the function. On the basis of the CRCL obtained with the three most common DT (4h, 6h, 8h), we divided the patients into three categories (CLPeak-time < 5h: "fast", 5-7h: "normal"; > 7h: "slow") for the best CRCL correspondence of the 4h, 6h or 8h exchanges respectively. Also the 8h/4h ratio was used to determine CLPeak-time. For each of the three categories there is a corresponding dialysis schedule for the best CRCL and UF results of the exchanges with DT of 4, 6 and 8 hours, plus the theoretical calculation of the daily CRCL obtainable ("fast": APD; "normal": CAPD 4 exchanges/DAPD 4 exchanges; "slow": CAPD 4 exchanges). The "CLPeak" dialysis prescription model therefore identifies the most advantageous DT for each patient by using the CRCL values of two 2.27% exchanges of 4 and 8h respectively. Functional classification into three categories may give a rational orientation to dialysis prescription in order to reach the maximum CRCL possible with the individual peritoneal transport rates.

Comparison of fast peritoneal equilibration tests with 1.36 and 3.86% dialysis solutions

At present dialysis solutions with different glucose concentrations are used for the peritoneal equilibration test (PET) and Fast-PET in peritoneal dialysis (PD). We compared the results of two Fast-PETs, using 1.36 and 3.86% solutions sequentially in 30 patients on PD treatment, to obtain information on peritoneal transport (D/P-4 h) and ultrafiltration rates. Creatinine, phosphorus and urea D/P-4 h in the two Fast-PETs were not statistically different, unlike those for potassium, beta 2-microglobulin and glucose. The creatinine and phosphorus D/P-4 h values in particular proved to be uninfluenced by the different dialysis solutions. The lack of correlation between the two Fast-PET ultrafiltration values confirmed the difficulty in interpreting this parameter, above all in the case of non-homologous Fast-PETs. We obtained useful indications for comparing different Fast-PET results, but were unable to reach a decisive conclusion regarding the best of the two dialysis solutions for this test.