Introduction

   Ventriculo-peritoneal shunts are the treatment of hydrocephalus. Usually, the peritoneal catheter is implanted via a mini-laparotomy approach in the right hypochondrium or in the midline.¹¹⁾ Injuries to the urinary bladder, gallbladder, vagina, and bowel all have been described with the open procedure.¹⁾¹²⁾ In addition, peritoneal catheter placement is unreliable, due to partly blind procedure. Not infrequently, the peritoneal end of the shunt has been identified as the cause for the dysfunction.⁶⁾ Laparoscopic assisted techniques could greatly reduce these potential morbidities through direct visualization of the peritoneal cavity, as well as reduce the risk of incisional hernia after laparostomy.^2)3)4)7)8) 
   We report a retrospective study of 102 patients with hydrocephalus who underwent ventriculo-peritoneal shunt surgery. 76 patients who underwent laparoscopy guided shunt surgery were compared with those of 26 patients who underwent surgery by non-laparoscopic approach at the same institution. 

Materials and Methods 

Patient Population 
   The study comprised 102 patients who had undergone ventriculo-peritoneal shunt between August 2005 and May 2008 for treatment of hydrocephalus at one institution. Seventy-six patients (38 men and 38 women) underwent laparoscopy assisted distal catheter placement, and in others 26 patients (14 men and 12 women), distal catheter placement was done by a mini-laparotomy approach. The causes of underlying hydrocephalus of two groups are summarized in Table 1. 

Shunt device 
   Codmann-HAKIM programmable valve shunt system were used in 73 cases (laparoscopy 63, mini-laparotomy 10), OSVII Flow regulated shunt system 18 cases (laparoscopy 4, mini-laparotomy 14), STRATA programmable valve shunt system 10 cases (laparoscopy 8, mini-laparotomy 2), and AESCULP programmable valve shunt system 1 case (laparoscopy 1). 

Operative Technique 
   All patients had undergone surgeries by the senior operators. The operation was performed under general anesthesia. Each patient was positioned supine with the head turned laterally for exposure parieto-temporal area. A gel roll was placed under the shoulders for neck and trunk support with extension. The head, neck, chest and abdomen were routinely prepared and draped. A sterile adhesive povidone-iodine impregnated film (Ioban^®) covered the operation field. The head of the patients was placed on a horse-shoe head rest, but if neuronavigation system was used, patient head was fixed by head fixator. Skin incision was made on parieto-occipital area or previous burr hole site (esp. Kocher's point, etc.). After ventricular catheter was inserted, shunt valve pressure was adjusted according to opening pressure. The transverse skin incision was made on RUQ area about 2cm for distinguish from appendectomy operavtive scar. The long passer was passed through subcutaneous tissue from the abdominal wound to the scalp wound. A relay station was made at the neck. The ventricular catheter and peritoneal catheter were connected to the reservoir. 
   In laparoscopic group, general surgeon estabilished pneumoperitoneum via Veress needle or Hansson technique. The puncture location was usually periumbilical, unless previous abdominal surgery required a different entry location as far as possible from previous scars. Intraabdominal pressure was kept between 13 and 15mmHg. We used a single 11-mm port through which a 0 operating telescope with a working channel was inserted. Under direct vision, the surgeon selects an adhesion-free location for the shunt entry point. At that point, a 5-mm skin incision was made, and the catheter tunneled from the neck to this point. Using a curved dissector, the abdominal wall is poked from the inside into the incision. The tip of the catheter is grasped and pulled into the peritoneal cavity(Fig. 1). The catheter was placed in an adhesion-free space and monitored for dripping of cerebrospinal fluid as the valve on the neck was pushed(Fig. 2). The intra-abdominal gas was evacuated, and the incisions were closed with intracutaneous absorbable stitches. 
   In mini-laparotomy group, general surgeon made a vertical incision, about 3cm on substernal area. After peritoneum found, the general surgeon made a 1cm sized incision. Confirming the bowel content, peritoneal catheter was placed in the peritoneal cavity and tied. The operations were performed by an interdisciplinary team. The laparoscopic & non-laparoscopic part of the operation were performed by the general surgeon at the same time that the cranial part of the procedure was conducted by the neurosurgeon. 

Statistical Analysis 
   For comparison of the two groups, the following factors were evaluated and analyzed; Age, sex, cause of hydrocephalus, type of shunt valve, mean operation time, shunt infection, and shunt distal catheter malfunction during follow-up. Pearson's chi-square test was used for comparison between mean operation time, shunt infection, shunt distal catheter malfunction. 
   SPSS(Statistical Package for Social Science ver.12K) was used for statistical analysis. The level of significant was p<0.05. 

Results 

   The results were summarized in Table 2. Mean age were fifty years old in mini-laparotomy group and fifty one years old in laparoscopic group. There was no statistically significant difference in age, sex, cause of hydrocephalus, and type of shunt valve. Shunt infections were observed in ten cases (13.2%) in laparoscopic group and in four cases (15.4%) in mini-laparotomy group, which was not statistically significant. Distal shunt malfunction rate were significantly lower in laparoscopic group (1.3%) compared to mini-laparotomy group (11.5%, P<0.05). The mean operation time was also shorter in laparoscopic group (108min, 45-190min) than that of mini-laparotomy group (146min, 75-255, P<0.005). No intra-operative complications were recorded in both group. 

Discussion 

   A minimally invasive technique using the Seldinger technique (The desired vessel or cavity in punctured with a sharp hollow needle called a trocar, with ultrasound guidance if necessary. A round-tipped guidewire is the advanced through the lumen of the trocar, and the trocar is withdrawn, A sheath or blunt cannula can now be passed over the guidewire into the cavity or vessel. After passing a sheath of tube, the guide wire is withdrawn.²³⁾) was described first in 1984⁹⁾, without direct visualization of the peritoneum. Since then, severeal studies described the laparoscopyguided insertion of the distal catheter in patients with hydrocephalus.^4)5)7)11) 
   In 1993, Basauri et all¹³⁾ reported a laparoscopic approach in the placement of the peritoneal portion of VPS. The advantage of the laparoscopic technique were: 1) enabling of direct visualization of peritoneal cavity; and 2) providing the ability to place the catheter tip into a selected region in an optimal location and test its function.¹⁴⁾ The successful application of laparoscopy has been reported for retrieval of a fractured catheter, revision of a malfunctioning shunt, and placement of a new catheter.^{10)15)16)17)18)19)20)} 
   One third of all shunt failures are thought to be due to malfunction of the distal catheter, which may be caused by dislocation, migration into the anterior abdominal wall, or obstruction.²¹⁾²²⁾ 
   During the follow-up period, three cases of shunt distal catheter malfunction (11.5%) in mini-laparoscopy group, but only one case of shunt distal catheter malfunction (1.3%) was observed in laparoscopic group (P<0.05). In contrast to laparoscopic placement of the catheter, visual control of the catheter position and confirmation of the CSF flow via distal catheter tip were not possible with the mini-laparoscopy approach. These could be the advantage of the laparoscopic technique. The results of the current study indicate that the risk for long-term complications attributable to distal shunt malfunction might be reduced when laparoscopic techniques were used to place the peritoneal catheter. 
   The mean operation time was also shorter in laparoscopic group (108min, 45~190min) than that of mini-laparotomy group (146min, 75~255min, P<0.05). There was a large fluctuation in the operation times in laparoscopic group from 75 to 255 minutes, and this was a result of the general surgeon was not always available immediately implantation of the peritoneal catheter. In spite of this, mean operation time reduced significantly (P<0.05) in laparoscopy group. 
   Shunt infections were observed in ten cases (13.2%) in laparoscopic group and in four cases (15.4%) in minilaparotomy group, which was not statistically significant. Difference of shunt infection rate between laparoscopy group and mini-laparotomy group was not statistical. 
   Overall, we believe the laparoscopic guided ventriculoperitoneal shunt described in this study had several advantages. 

Conclusion 

   The laparoscopic ventriculo-peritoneal technique that we had presented was a simple procedure that provides benefits of reducing distal catheter malfunction and operation time. Still longer follow up more cases observation is necessary, we suggest that laparoscopic guided placement of the ventriculo-peritoneal shunt in hydrocephalus patients has reducing distal catheter malfunction, mean operation time. 

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