Laparoscopic and robotic specimen retrieval system (Modified Nadiad Bag): Validation and cost-effectiveness study model

15 Sep.,2022

 

Disposable Specimen Retrieval Bags

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Our design of retrieval system offers a cost-effective option which is easy to make, without the risk of tumor seeding and without the need for separate access sheath. It's a retrieval system which has proved its efficacy in laparoscopic as well as robotic procedures with no bearing on the expertise of the surgeon involved.

The retrieval times, the organ size (largest dimension) and specimen weight were records for each case. Multivariate analysis of the data was done and we extrapolated the retrieval time with organ size, specimen weight and expertise of the surgeon. There was no significant difference among expert surgeons and novice surgeons with regards to retrieval times (p value = 0.29), with regards to organ size (p value = 0.83) and with regards to specimen weight (p value = 0.99).

The components of the modified Nadiad bag are a polyethylene roll, fishnet thread, and a 5 Fr ureteral catheter. The bag is indigenously made in our institute and used for organ retrieval after proper sterilization. The video recordings of entrapments and retrievals done over the past few months were reviewed. The procedures under review in which the bag was used were: Robot Assisted Radical Prostatectomy (50 cases), laparoscopic radical nephrectomy (50 cases), laparoscopic simple nephrectomy (50 cases) and laparoscopic adrenalectomy (18 cases). We also compared the retrieval time with experts and novices.

We have devised a solution, a bag which is not only cost effective but is also as effective as the available devices. This bag was initially described as the Nadiad Bag.[ 5 ] We performed a validation study in various urological procedures and assessed the safety, efficacy and cost-effectiveness. We also evaluate the efficacy by validating the entrapment time and retrieval time.

The currently available specimen retrieval bags cost in the range of 25–100 USD.[ 1 , 2 , 3 , 4 ] All laparoscopic surgeons have their indigenous ways of entrapping, the specimen using the available glove finger, etc.[ 4 ] However, the drawbacks of all these indigenous entrapment materials include the inability to keep the ‘mouth’ of the entrapment device open. This increases the difficulty for entrapment besides adding to the operating time. This novel ‘homemade’ bags do not ensure retrieval without spillage.

Specific retrieval forms an integral part of any ablative procedure. The key requisites for any successful entrapment of the specimen include expeditious retrieval and ensuring that the specimen is not mutilated which may hamper proper histological interpretation. There are also concerns regarding oncological principles such as spillage.

The present study was conducted at Muljibhai Patel Urological Hospital, Nadiad, India. The video recordings of entrapments and retrievals done over the past few months were reviewed. The procedures under review in which the bag was used were as follows: robot-assisted radical prostatectomy (50 cases), laparoscopic radical nephrectomy (50 cases), laparoscopic simple nephrectomy (50 cases) and laparoscopic adrenalectomy (18 cases). We also compared the retrieval time with experts and novices. The compatibility and permeability testing of the bag was performed using the innovative saline fill technique.

The key feature of the bag and the idea which makes this an innovation is the ureteric catheter. In all indigenous bags or the homemade bags, there is a shortcoming that the mouth of the bag cannot be kept open as the plastic keeps on folding on itself. We thought that we need to device a mechanism by which the mouth remains open. This can be kept open using a stiff material. The material can be a ureteric catheter.

Ever since its induction in routine ablative laparoscopic procedures at our institute we have made two modifications as follows: (1) The use of fishnet thread instead of nylon sutures as fishnet thread is more compliant with plastic since it does not tear through the plastic bag when pulled which was the case with nylon thread and fishnet thread is more economical. (2) The lower end of the bag is stitched on a sewing machine which was previously sealed with an autoseal device. Earlier bags sealed with an autoseal device often showed dehiscence and opened when the specimen was placed.

During the operative procedure, the bag introduction is performed through the 10-mm port with the help of an atraumatic grasper without any special introducer sheath. Two laparoscopic instruments are required to open, place the specimen within and close the bag [Figure - ]. Once the specimen is secured in the bag, the ureteric catheter is pulled out with a laparoscopic grasper and the fishnet thread is pulled to close the open mouth of the bag. The bag can be retrieved though any of the ports by extending the incision if required. The bag is manufactured at Muljibhai Patel Urological Hospital research laboratory.

The components of the retrieval bag are a transparent plastic bag roll, fishnet thread and a 5 Fr ureteral catheter. The plastic bag rolls have a tubular construction throughout their length and three different sizes are available in the market [ ].[ 6 ] These bag rolls are unwound to the required length and cut according to the individual requirement [ ]. One end of the plastic bag roll is stitched completely and sealed which becomes the base of the bag [ ]. The corners of the other end (mouth) of the bag are cut up to 3 cm [ ]. The other corner of the mouth being cut in a similar manner [ ]. The plastic slip so created after cutting the corner is folded outwards on itself to create a tunnel [ ]. The folded edge is then stitched to create a tunnel [ ]. In a similar manner, the other slip of plastic is folded outwards on itself and stitched to create a second tunnel [ ]. The final bag so created has a sealed lower end and the mouth of the bag with two tunnels at the edges [Figure and ]. A loop is created at the end of the fishnet thread. The ureteric catheter is passed through this loop for ease of insertion of catheter in the tunnel [ ]. The folded tunnel accommodates the 5F ureteral catheter and fishnet thread [ ]. Finally, the bag is folded compactly with rubber bands wound tightly around it and sealed in a plastic bag and sterilised using plasma steriliser before use.

Multivariate analysis of the data was performed, and we extrapolated the retrieval time with organ size, specimen weight and expertise of the surgeon [ ]. Statistical tests applied were Levene's test for equality of variances and t-test for equality of means. There was no statistically significant difference between expert surgeons and novice surgeons with regard to retrieval times (P = 0.29), with regard to organ size (P = 0.83) and with regard to specimen weight (P = 0.99).

The saline fill test was done in all models of the bag. It did not reveal any leak of saline.

The retrieval times for all the above-mentioned procedures were collected. The organ size (largest dimension) and specimen weight were also recorded for each case [ ].

DISCUSSION

Even since the introduction of the laparoscopy as a modality in the realm of urology, it has gained widespread acceptance for various reasons such as shorter hospital stay, less postoperative pain and better cosmesis. However, one of the challenges faced in laparoscopic ablative surgeries is the extraction of the excised organ specimen.

Direct specimen retrieval attempted initially often required larger incisions and thus increasing the risk of an incisional hernia besides compromising cosmesis.

With the intent to tackle this challenge Clayman and associates designed the first organ bag (LapSac), especially for laparoscopic nephrectomy.[7] Since then a number of versions of specimen retrieval systems have been developed and made commercially available for specimen retrieval intact as well as morcellation with specimen retrieval.

Currently, commercially available retrieval systems individually have their own advantages and disadvantages. The Pleatman sac by design has its mouth continuously open allowing the specimen placed inside to slip out while extraction. The Endocatch bag turns irretrievable once the purse string is activated closing and tearing of the plastic bag. The LapSac bag (Cook Urological) which is one of the most commonly used bags for morcellation of nephrectomy specimen often requires placement of two or three additional ports to manoeuvre specimen into the bag. This also further demands a learning curve to use this bag. The Lap Bag, Extraction Bag, Endobag, Endopouch and Endocatch are some retrieval systems which require an additional introducer sheath to deploy the bag. The Espiner bag has been proven to have poor impermeability.[8]

The material used in manufacturing of the bags does play an important role in the success or failure of retrieval of an intact specimen. Singhvi and associates analysed the physical properties of the endoscopic retrieval systems and revealed that plastic systems could be delivered intact with little force when compared to fabric systems which tore in response to a significantly greater force. In addition, as plastic bags are nonporous, cells from neoplastic lesions are less like to leak thus reducing the risk of tumour seeding.[9]

Above all, a major shortcoming associated with these retrieval systems is the cost. The cost factor does come into play in third world scenarios where the surgeons have to work with limited resources while maintaining the oncological principles and avoid compromising the quality of care. The cost of these retrieval systems ranges from $25 to 100; thus, increasing the cost of surgery to an extent discouraging the patients from opting for minimal access modality.

Keeping all these aspects in mind, we designed a retrieval bag as an economical option for specimen extraction. The ureteric catheter placed in the tunnel of the bag helps to keep the mouth of the bag open owing to its inherent stiffness with certain degree of malleability. This eases the entrapment of the specimen without the worry of edges of the bag folding inside. The bag being made of transparent plastic and sealed with an autoseal device ensures intact specimen retrieval without the risk of tumour seeding. The retrieval system does not require any separate introducer sheath for deployment or any additional ports for manoeuvring. Finally, the entire cost of making one bag turned out to be $1.20.

These observations do show the potential impact of this innovation can have in benefitting a large number of patients, especially from the underprivileged sections of the society. These are the patients for whom cost of a procedure is a factor that dictates whether he/she will opt for medical intervention or not.

Furthermore, the statistical analysis in this study clearly shows that the experience of the surgeon (expert or novice) did not have an impact on the retrieval time of the specimen. This finding suggests that the use of our retrieval system did not require the surgeons to undergo a steep learning curve.