Post-operative pain in needlescopic versus conventional laparoscopic cholecystectomy: a prospective randomised trial

M. LOOK, S.P. CHEW, Y.C. TAN, S.E. LIEW, D.M.O. CHEONG, J.C.H. TAN, S.B. WEE, C.H. TEH and C.H. LOW
Department of Surgery, Tan Tock Seng Hospital, Singapore

Introduction Patients and methods

Results  Discussion References

Background: Needlescopic cholecystectomy (NC) utilises instruments and ports smaller than 3 mm in diameter compared with the 5 mm ones used in conventional laparoscopic cholecystectomy (LC). Post-operative pain control and recovery has been thought to be superior in NC, when compared with historical controls with LC, but has not been proven in a prospective fashion. Patients and methods: A prospective randomised trial of NC versus LC for patients with symptomatic gallstone disease, with standardisation of post-operative analgesia and daily assessment of post-operative pain, using a 5-point visual analogue scale. Results: There were 64 eligible patients randomised into NC (28) and LC (36). Four patients who had NC were converted to LC due to technical problems. Another three and six patients from the NC and LC groups, respectively, had conversion to open surgery. Postoperative pain scores were low in both groups. Mean pain scores for those with successful NC and LC were: 1.24 versus 1.43 for the day of operation (P=0.49), 0.86 versus 0.83 for the first day post-operatively (P=0.92) and 0.75 versus 0.81 for the second post-operative day (P=0.87). The mean number of intra-muscular analgesic injections required were 0.76 versus 0.83 after NC and LC, respectively (P=0.93). There were no significant differences between the two groups in the time taken to return to feeding, eating a normal diet and discharge from hospital. Conclusion: There is no advantage of NC over LC in terms of post-operative pain or recovery. Nevertheless, NC can be performed safely and expediently and has an excellent cosmetic outcome and high patient acceptability.

Keywords: Cholecystectomy, laparoscopic, needlescopic, post-operative pain

J.R.Coll.Surg.Edinb., 46, June 2001, 138-142 

INTRODUCTION

Since the introduction of laparoscopic cholecystectomy (LC) as a minimally invasive alternative to the conventional open cholecystectomy, the procedure has quickly become the treatment of choice for gallbladder disease. More than any other laparoscopic procedure, LC has epitomised the advantages of minimal access surgery. It has been shown to be consistently superior in terms of post-operative recovery and has resulted in earlier discharge from hospital and return to full activity. The main reason for these improvements has been the replacement of a long surgical incision with several small port site incisions. The expected reduction in postoperative pain, as a consequence, has also been proven by prospective trials.^1-4

The earliest LCs were performed with videoscopes, 10-12 mm in diameter, and laparoscopic instruments, 5-12 mm in diameter. Since then, advances in technology have led to significant improvements in design and handling as well as a reduction in instrument size. The standard LC is now usually performed with three 5 mm ports and a videoscope inserted through a 10-12 mm umbilical camera port. Recently, however, a new generation of instruments that are even smaller has aroused considerable interests. These so-called ‘needlescopic’ instruments have been defined as those with a diameter of 3 mm or less.⁵

Needlescopic cholecystectomy (NC) has been thought by some to be superior to LC in the same way that the latter has proved to be better than a conventional open procedure. This belief is based on the experience of reduced post-operative pain with smaller ports used. Detractors, on the other hand, argue that the tissue trauma associated with standard 5 mm LC ports is already minimal and any further benefit from miniaturisation is negligible. Moreover, at least one 10-12 mm port (usually also the umbilical camera port) is mandatory for retrieval of the gallbladder specimen in both NC and LC procedures and this may negate whatever benefit is obtained by the use of smaller instrument ports.

This issue has remained controversial and since part of the demand for NC is consumer-driven, there is a fear that any proclaimed advantage may be only perceptual.6 Although there are reports claiming a decreased need for post-operative analgesia in NC patients, this was in comparison with historical LC controls.^5,7 Our aim, therefore, was to design a prospective randomised trial to compare the post-operative pain and analgesic requirements in patients undergoing NC and LC.

PATIENTS AND METHODS

Patients who presented for elective cholecystectomy were considered for the trial. All patients had symptomatic gallstones confirmed by abdominal ultrasonography. Diagnostic and therapeutic endoscopic retrograde cholangio-pancreatogram was performed pre-operatively, where indicated. Patients who required laparoscopic cholangiography or common bile duct exploration were excluded. All the patients were assessed to be fit for anaesthesia and laparoscopic surgery. The patient’s age and history of previous abdominal surgery were not considered to be contraindications for the trial.

Randomisation was done in the operating room just prior to surgery by the drawing of closed lots prepared in blocks of 20. The patients were blinded to the procedure to be performed and after surgery received identical opaque occlusive dressings. All the surgical procedures were standardised and performed by surgeons experienced in laparoscopic cholecystectomy. Open insertion of a 10 mm umbilical port was done by the cutdown technique for the creation of the pneumoperitoneum and for the introduction of a 10 mm videolaparoscope. Diagnostic laparoscopy was carried out. Patients with acutely inflamed gallbladders or concomitant pathology requiring intervention were excluded. Although we are able to perform a NC for acute cholecystitis, we did not include these patients in the trial as this was technically a more difficult operation with longer operating times and higher conversion rates. A total of 72 patients were randomised. After exclusion of ineligible patients, 64 cases were available for analysis; 28 had been randomised to the NC group and 36 to the LC group. No other patients were withdrawn and no protocol violations were encountered.

For the LC group, the operation followed the standard laparoscopic cholecystectomy procedure. Three 5 mm instrument ports were used: one operating port in the epigastrium and two retraction ports in the sub-costal margin. A 5 mm clip applicator was used for the clipping of the cystic duct and artery. For the NC group, all three ports were substituted with non-disposable 3 mm instrument ports. The procedure was identical except during the clipping of the cystic duct and artery. The camera was exchanged from the 10 mm to a 3 mm videolaparoscope and inserted into the epigastric port, freeing the 10 mm umbilical port for the application of standard laparoscopic clips. As the orientation and optical quality during this process is sub-optimal, the 10 mm videolaparoscope is re-introduced to check on the position of the clips before division of the cystic duct and artery. In both LC and NC groups, retrieval of the gallbladder was achieved with the use of an endo-pouch placed through the 10 mm umbilical port. Only the 10 mm port site required musculo-fascial closure. Skin was closed with interrupted Prolene sutures.

Post-operatively, all the patients were allowed to drink and eat when deemed appropriate. Nausea was treated with intra-muscular injections of metoclopramide. Ambulation was routinely encouraged and all patients were discharged home when they were pain free and felt able to leave hospital.

Post-operative analgesia was standardised to oral naproxen 500 mg twice a day or a suitable alternative, if this was contraindicated. All the patients were free to request further analgesia - intra-muscular pethidine (1 mg per kg bodyweight 8 hourly) -if they required more analgesia for pain control. Pain score was recorded daily beginning with the operation day after full recovery from the general anaesthesia. A five-point visual analogue scale was used: 0 = no pain, 1 = mild pain, 2 = moderate pain, 3 = severe pain and 4 = unbearable pain. The highest pain score recorded for each day was used if more than one differing score were obtained in each 24-hour period.

Statistical analysis

A previously published non-randomised study showed that post-operative analgesia requirements for NC patients were 70% lower than those undergoing LC.5 In addition, 47% of NC patients did not require narcotics compared with 9% of LC cases. Based on the assumption that an effect size of this magnitude would be clinically significant, we estimated that a minimum of 21 patients will be required in each arm of a randomised trial to detect a statistical difference at a significance level (a) of 5% and power (1-ß) of 80%. To allow for excluded patients, the trial was fixed to run between January to September 1998 with the intention of enrolling at least 60 patients in total.

The data for the two groups of patients were analysed on an intention to treat basis or after excluding cases requiring conversion when this was more appropriate. This is clarified for each result reported. Statistical analysis was carried out using the chi-square and Fisher’s exact test to evaluate association between groups in contingency tables. Pain scores and analgesia requirements were compared with the Mann-Whitney U test.

RESULTS

The mean age of our patients was 52.2 years (range 20-78).

The two groups of patients were comparable in terms of demographic data and co-morbid disease (Table 1).

Table 1: Demographic data of patients studied

Of the 28 patients initially randomised to the NC group, 21 (75%) needlescopic operations were successfully completed. Four cases (14.3%) required conversion to a LC procedure by the replacement of one or more ports with standard 5 mm LC ports and instruments. Three of these cases required one port and one case required two ports to complete the operation. None of the cases needed full conversion of all three ports. Another three cases (10.7%) in the NC group were converted to a standard open operation. In comparison, six cases out of the 36 patients in the LC group (16.7%) needed conversion to an open cholecystectomy.

The reason for conversion of an NC procedure to LC were usually technical. The delicate needlescopic instruments were occasionally unable to provide adequate gallbladder retraction. In both the NC and LC groups, conversion to a standard open cholecystectomy was indicated when technical difficulties, adhesions or an inability to delineate the normal anatomy made it unsafe or impossible to proceed with minimal access surgery. Two cases in the LC group had biliary injury recognised intra-operatively and this required conversion for repair. There were no other cases of biliary injury detected post-operatively and no other delayed complications in either group, after a minimum follow-up period of one year.

There were no significant differences in the operating times taken for the NC and LC procedures. The mean operation time was 72.1 minutes (SD 21.6) for NC and 75.1 minutes (SD 39.8) for LC. If all cases requiring conversion to LC or open surgery were excluded, the mean operating times were 66.2 min (SD 18.6) and 65.2 min (SD 29.6) for a successful NC and LC, respectively.

The post-operative pain scores and analgesic requirements were analysed after exclusion of patients who had conversion to an open procedure. Patients who had conversions from NC to LC were also excluded from either groups to prevent contamination of results as the deployment of ports did not conform to that specified for either NC or LC. There were, therefore, 21 and 30 patients in the NC and LC group, respectively. Their pain scores recorded on the day of operation, the first and second postoperative day are shown in Table 2.

Table 2: Post-operative pain scores of patients studied

Pain scores were generally low for both groups. The majority had either no pain or mild pain (score = 0 or 1) and no patient recorded the maximum score of 4. The mean pain scores for the NC and LC groups were: 1.24 versus 1.43 for the day of surgery, 0.86 versus 0.83 for the first post-operative day and 0.75 versus 0.81 for the second day following surgery. There were no significant difference in post-operative pain between the two groups over all 3 days (P=0.49, P=0.92 and P=0.87). After the second postoperative day the number of patients still hospitalised were too small for meaningful comparison of pain scores.

Satisfactory pain control was easily achieved in both groups of patients by oral analgesics. No intra-muscular analgesic injections were required in 42.9% of the NC patients and 50% of the LC patients. There was also no statistical difference in the parenteral analgesic requirements in both groups (P=0.93). The mean number of intra-muscular injections required was 0.76 and 0.83 in the NC and LC groups, respectively.

The majority of patients in both groups were able to return to oral food intake quickly after surgery (Table 3). In the group which had successful NC, 90.5% could retain liquid feeds on the day of operation and 95.2% were ingesting solids by the first post-operative day. The corresponding figures were 83.3% and 86.7% for the LC group. Similarly, return to activity was rapid in both groups and the majority of patients were able to be discharged by the second post-operative day (81% and 90% for the NC and LC groups, respectively). There were no significant differences between the NC and LC groups in terms of rapidity of return to oral intake of food (P=0.38), normal diet (P=0.20) and discharge (P=0.62).

Table 3: Post-operative time to return to liquid feeds, solid diet and discharge from hospital

DISCUSSION

Needlescopic surgery, otherwise known as mini-site, micro-laparoscopic or mini-laparoscopic surgery, evolved as a natural development of laparoscopic surgery with the advancement in technical skills of surgeons in combination with the miniaturisation of equipment. Needlescopic instruments are usually between 1.9 and 3 mm in diameter. Compared with the larger laparoscopic versions, they are more fragile and, therefore, easily bowed if subjected to lateral forces about a fixed fulcrum at the point of entry into the abdominal cavity. They require gentle tissue handling techniques and may not be adequate if heavy retraction is required. Careful electro-cautery must also be used as the thinner instruments tend to be less well insulated. Nevertheless, many laparoscopic procedures are suitable for using these instruments, either exclusively or in combination with conventional laparoscopic ones, with only minor modifications in techniques required. Needlescopic procedures have already been described for cholecystectomy, appendicectomy, herniorrhaphy, splenectomy, adrenalectomy and fundoplication. ^5,8

Needlescopes currently range between 1.2 and 3 mm in diameter and utilise a fibre-optic system. The optical quality is acceptable but inferior in terms of brightness and resolution, when compared with the conventional Hopkins rod-lens array employed in conventional laparoscopes. The field of vision is also constricted, resulting in a demagnification effect. An undesirable consequence of this is the tendency to advance the camera towards the operating field to improve the image, but in turn causing mechanical interference with the operating instruments. As such, it is preferable to restrict the use of needlescopes whenever possible. In procedures where a 10-12 mm port is necessary for specimen retrieval, this port can be used for conventional laparoscopes for most parts of the operation. In the NC for example, the needlescope is only required for visualising the deployment of clips to the cystic duct and artery. Clips applicators for use with needlescopic ports are not available at present and are not likely to be developed given the limitation of size.

The possible advantage of NC over LC has been suggested by several authors but not proven in a prospective randomised fashion. We analysed ours results for pain scores and analgesia requirements as per protocol, i.e. NC versus LC after exclusion of converted cases, rather than on an intention to treat basis as the main aim of the study was to elucidate any possible advantages of a successful NC compared with a conventional LC. We recognise that this negates partly the benefits of randomisation but this was deemed preferable to the possibility of obscuring a true difference by contamination of a small sample with a relatively large number of converted cases.

Our findings suggest that there is no difference in the postoperative pain between these two groups of patients; both groups of patients recording low pain scores throughout the post-operative period. This is not surprising as much of the patient’s pain and discomfort is usually related to the number of 10-12 mm ports used and not the smaller 3 or 5 mm instrument ports.

Half of our patients in both the NC and LC groups did not require any post-operative intra-muscular analgesia. Routine oral analgesia was usually sufficient and this suggests that cholecystectomy can be performed as a day surgery procedure in carefully selected patients with post-operative follow-up by a community nurse. This has already been shown by some centres to be feasible although a prospective trial has reported no cost benefit for this practice, when compared with overnight-stay cholecystectomy.⁹

The functional recovery was also similar in our two groups of patients with equally rapid return to feeding, normal diet and activity. It is unlikely that the needlescopic operation confers any additional advantage in these respects. On the other hand, cosmesis is superior in the NC group. We did not compare this in our patients as there is considerable subjectivity in any attempt to score wounds cosmetically. Nevertheless, it has been our experience, and that of others, that needlescopic port sites heal with a virtually imperceptible scar and result in an excellent aesthetic outcome.^5,7,10 There is also a lower risk of post-operative port-site hernia, although this advantage is theoretical as this complication is rare and only reported anecdotally even for conventional 5 mm port sites. ¹¹

We found that needlescopic gallbladder surgery can be performed safely and expediently. Three quarters of cases randomised to a NC procedure could be completed successfully. The operating times for these patients were similar to those who had LC carried out. There were two cases of biliary injury in this trial, both from the LC group. This was unfortunate but does not reflect the overall rate of laparoscopic complications in our institution. In an audit of laparoscopic cholecystectomy in four major hospitals in Singapore, the incidence of bile duct injury was 0.43% out of 4,445 operations (including all the cases done in our hospital from 1990 to 31 December 1997).¹² This figure compares favourably with the range of 0.33% to 0.6% reported from Europe and the USA.^13,14

This high rate of biliary injury in the LC group, therefore, was likely to be incidental and not related to the trial. Nevertheless, we strongly advocate conversion to open surgery should there be doubts about the anatomy or when technical difficulties preclude a safe operation. This policy also explains the high rate of conversion to open surgery encountered in both the NC and LC groups. However, NC itself is not associated with a higher risk of conversion to open surgery. Technical limitations encountered during NC due to the fine instruments can usually be resolved by early conversion to a LC approach rather than struggling with inadequate retraction or exposure. In our experience, replacement of one or two ports is usually sufficient to complete the operation with little impairment to the postoperative outcome. Overall, our policy has resulted in a conversion rate to LC and open cholecystectomy which is higher than that reported by others but we feel that this should not be construed as failure - a point we hope would not be lost on those embarking on the learning curve of needlescopic surgery.^5,7

REFERENCES

1. Squirrell DM, Majeed AW, Troy G, Peacock JE, Nicholl JP, Johnson AG. A randomised, prospective, blinded comparison of post-operative pain, metabolic response, and perceived health after laparosopic and small incision cholecystectomy. Surgery 1998; 123: 485-95
2. McMahon AJ, Russell IT, Ramsay G, Sunderland G, Baxter JN, Anderson JR, Galloway D, O’Dwyer PJ. Laparoscopic and mini-laparotomy cholecystectomy: a randomised trial comparing post-operative pain and pulmonary function. Surgery 1994; 115: 53-9
3. Kum CK, Wong CW, Goh PM, Ti TK. Comparative study of pain level and analgesic requirement after laparoscopic and open cholecystectomy. Surg Laparosc Endosc 1994; 4: 139-41
4. Chan HS, Ha XF, Ooi PJ, Mack P. A prospective comparative study between conventional and laparoscopic cholecystectomy. Singapore Med J 1995; 36: 406-9
5. Gagner M, Garcia-Ruiz A. Technical aspects of minimally invasive abdominal surgery performed with needlescopic instruments. Surg Laparosc Endosc 1998; 8: 171-9
6. Mar Fan MJ, Chan ST. ‘Needlescopic’ (minilaparoscopic) surgery: necessary or unnecessary? Aust N Z J Surg 1998; 68: 628-9
7. Ngoi SS, Goh P, Kok K, Kum CK, Cheah WK. Needlescopic or mini-site cholecystectomy. Surg Endosc 1999; 13: 303-5
8. Ferzli G, Sayad P, Nabagiez J. Needlescopic extra-peritoneal repair of inguinal hernias. Surg Endosc 1999; 13: 822-3
9. Hollington P, Toogood GJ, Padbury RTA. A prospective randomised trial of day-stay only versus overnight-stay laparoscopic cholecystectomy. Aust N Z J Surg 1999; 69: 841-3
10. Kimura T, Sakuramachi S, Yoshida M, Kobayashi T, Takeuchi Y. Laparoscopic cholecystectomy using fine-caliber instruments. Surg Endosc 1998; 12: 283-6
11. Toub DB, Campion MJ. Omental herniation through a 5 mm laparoscopic cannula site. J Am Assoc Gynaecol Laparoscopy 1994; 1: 413-4
12. Ooi LLPJ, Goh YC, Chew SP, Tay KH, Foo E, Low CH, Chng HC, Chan STS, Soo KC. Bile duct injuries during laparoscopic cholecystectomy: a collective experience of four teaching hospitals and results of repair. Aust N Z J Surg 1999; 69: 844-6
13. Jatzko GR, Lisborg PH, Pertl Am, Stettner HM. Multivariate comparison of complications after laparoscopic cholecystectomy and open cholecystectomy. Ann Surg 1995; 221: 381-6
14. Deziel DJ, Millikan KW, Economou SG, Doolas A, Ko ST, Aivan M. Complications of laparoscopic cholecystectomy: a national survey of 4292 hospitals and an analysis of 77,604 cases. Am J Surg 1993; 165: 9-13

Copyright date: 27th February 2001

Correspondence: Mr Melvin Look, Department of Surgery, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433

E-mail: melvin_look@notes.ttsh.gov.sg

©2001 The Royal College of Surgeons of Edinburgh, J.R.Coll.Surg.Edinb.