Calculating the learning cunre for laparoscopic splenectomy

Calculating the learning cunre for laparoscopic splenectomy

Ahmed Kamal, MD; Hamed Abo Steit, MRCS, MD;

Haitham Elmaleh, MRCS,MD; Ahmed Elnabil, MRCS, MD Department of General surgery, Ain Shams University, Cairo, Egypt.

Background & objectives: Laparoscopic  splenectomy had become the golden standard for elective splenectomy, as it is feasible, safe and provides many advantages to the patients in comparison to open splenectomy. However, a learning curve exists for mastering the procedure and defining will be helpful in designing a training program for laparoscopic splenectomy.

Methods: 57 patients underwent elective laparoscopic splenectomy for different indications in our hospital between August 2011 and September 2013. Patients' data whether preoperative, operative or postoperative  were collected, subdivided in 10 cases groups and certain outcome measures were statistically analyzed to identify the learning curve.

Results:  Laparoscopic  splenectomy was done for all patients. The mean operative times in the 3rd, 4th, 5th and 6th groups were significantly shorter than the 1st and 2nd groups. There was a trend toward decreased  blood loss in the latter groups (3rd, 4th, 5th and 61h), and the differences  between them  and the first two groups were statistically  significant. There was a trend of high postoperative  complications and conversion rate in the first group in relation to the other groups, but a statistically significant difference between groups couldn't be found. Similarly, there was a trend towards decreased period of ileus with the consecutive groups; but a statistically significant difference couldn t be shown.  A statistically  significant difference in hospital stay was found between the consecutive groups. The results showed that the outcome measures were seen to improve with the advancement of the experience with a plateau reached after 20-30 cases oflaparoscopic splenectomy.

Conclusion: Laparoscopic  splenectomy  can be done  safely by experienced  laparoscopic surgeons. A learning curve for mastering the procedure is 20-30 cases, after which the outcome parameters nearly reaches a plateau.

Introduction:

Splenectomy    is   performed    either    as causal or symptomatic therapy for numerous indications. Formerly, open splenectomy represented the traditional for patients with different  indications   of  splenectomy.l   The first   successful   laparoscopic   splenectomy was  reported  by  Delaitre  and  Maignien  in 1991,2 and since then, the procedure had been

adopted  as the standard  technique  for most indications  for  splenectomy  throughout  the world,  specially  normal  sized  spleen.3 The wide acceptance oflaparoscopic splenectomy is based on the benefits it offers compared to open splenectomy, which  include decreased

analgesia   use,    earlier   initiation     of   oral diet, decreased length of stay, and fewer complications, together with comparable clinical outcomes.4 Moreover, the growing experience  and  the  advances  in  equipment had made this approach feasible in situations that were thought to be contraindications  in the past.3

These advantages are dependent, however, on the surgeon's  experience and ability to perform the procedure expeditiously and without complication. As described with other laparoscopic techniques, there is a learning curve as new procedures are introduced.5

Some authors define the learning curve as a decrease in operating time, a decrease in conversion rate, or a decrease in complication rate  that  can  be  achieved   after  a  certain number of cases.6,7,8,9

Surgeons,  who  are seeking  to  undertake this   procedure,   should   be   aware   that   it is considered an advanced laparoscopic procedure and is associated with a significant learning  curve  that  has  yet  to  be  defined. This is also important in the planning of structured training programs for laparoscopic splenectomy in any educational hospital.

In this  study, we are trying to define the learning  curve for laparoscopic  splenectomy in our hospital in order to define those  who can be granted the privilege of independently performing the procedure and who to structure the training for it  in our training program.

Patients and methods:

The study was carried  out in Ain Shams University  hospitals  during  the  period between August 2011 and September 2013. Patients  who  were  referred  to  our  surgical team    with    indications    of    splenectomy during that period were prepared for elective laparoscopic  splenectomy.  Each  of  the patients was operated on by an experienced surgeon who was just starting to practice laparoscopic   splenectomy   (all  cases  were done by the same team).

Preoperative preparation of all patients included vaccinations with polyvalent pneumococcal,  polyvalent  meningococcal, and Haemophilus influenza type B conjugate vaccmes,     and    preoperative     antibiotics. Other preoperative measures were individualized according to each patient condition.   Transfusion   of  blood   products, such as platelets, packed red blood cells, or gamma  globulin,  was performed  according to  the  plane  of  the  referring  hematologist, or anesthesiologist. Routine preoperative ultrasound  to  determine  splenic  s1ze. An informed consent was obtained from the patients before operation.

The procedure  is performed  with the patient under general anesthesia with endotracheal  entubation. A nasogastric  tube is  inserted  to  decompress  the  stomach  and a Foley's  catheter  is inserted to the bladder.

The patient is put in the supine position with legs apart and a 20° head-up tilt (reversed Trendelenburg   position).   The  surgeon operates  in the  "French" position  (between the  patient's  legs) with the camera assistant on  his  left  and  the  second  assistant  to the right. A 12 mm port is inserted  at the level of  the  umbilicus  using the  open  technique and    carbon    dioxide    pneumoperitoneum is induced. Thorough exploration of the abdomen, pelvis, and omentum for accessory spleens  using a 30° angled scope  is carried out at first.  Then, 3 more trocars are inserted under direct vision  as shown  in Figure (1). In cases of larger spleens, port positions and size were altered according to the size of the spleen. The table  is then  tilted  30° to the  right.

The  stomach  is  retracted  medially  through the left 5-mm trocar to expose the spleen after the  omentum  has  been  displaced  inferiorly. Then  the  phrenicocolic  and the  splenocolic ligaments  are  incised  near  the  lower  pole using the Ligasure through the right 12-mm port. The lower  pole of the spleen  is gently lifted   with   a   closed   instrument   without grasping   which   is   introduced   through   a 5-mm port to expose the splenic  hilum and the tail of the pancreas. A window above the tail of the pancreas is created to permit the application of a stapling device and to control all hilar vessels. We used an Endo-GIA with a vascular (white) cartridge to transect the hilum. After control of the hilar vessels, the short  gastric vessels  are then  divided using the Ligasure. After that, proper hemostasis is ensured.  The specimen  is then  inserted  into a plastic bag, and the spleen is morcellated using a long forceps and the bag is extracted through enlarging of the port sites. After reestablishing of pneumoperitoneum, fast reexploration is done to ensure proper hemostasis.  A redivac  is  advanced  through the left trocar site and placed in the left subphrenic space. The operation is completed by closure of all trocar ports.

Postoperatively, the patients are observed for  vital   data,  return   of  bowel  functions and   wound    complications.    The   patients were   discharged   after   return   of   normal bowel  functions,   drain  removed   and  any complication ruled out.

Perioperative parameters were assessed, including patient age and sex, surgical indication for splenectomy, American society of Anesthesiology  (ASA) score, other comorbidities, size ofthe longitudinal access of the spleen, preoperative hemoglobin and platelet count and body mass index. Operative data were assessed including  operative time in minutes, presence of technical difficulty, estimated    blood    loss,    requirement     for blood product transfusion, spleen specimen weight   and  the   need   for   conversion   to open splenectomy. Postoperative data was assessed  including  period  of  ileus,  time  to oral intake, length of hospital stay, the need for reoperation  and postoperative  morbidity or mortality.

Calculation ofthe learning curve:

To  define  the  learning  curve,  the  cases were  divided  into  sequential  groups  of  10 cases and the parameters used for calculation of the  learning  curve  (operative  time, estimated    intraoperative    blood   loss,   the need for conversion to open splenectomy, postoperative  complications or mortality, period of ileus and hospital stay) were recorded and evaluated for statistical significance. The groups were compared using the independent sample  t-test  for  continuous  variables  and chi-square test for categorical variables. All calculations  were  done using  SPSS  version

21 statistical software.

Results:

This     study     included     57     patients. The indication for splenectomy was thrombocytopenia in all patients. The cause ofthrombocytopenia was ITP in 36 (63.2%) patients, spherocytosis in 13 (22.8%) patients, chronic lymphocytic leukemia (CLL) in 5 (8.8%) patients and lymphoma in 3 (5.3%) patients as shown in Table (1).

The study group consisted of 23 (40.4%)

males and 34 (59.6%)females. The mean age of the patients was 27.5 ± 8.7 years with range from 16-52 years. The mean longitudinal splenic dimension was 14 ± 4.9 em with range from 12 to 19 em. The preoperative data are

shown in Table (2).

Laparoscopic  splenectomy  was  done for all patients. The operation was successfully completed  laparoscopically  (no conversion) in 52 patients (91.2%). The conversion was done in 5 cases (8.8%) due to bleeding which couldn't  be  controlled.  The mean  operative time was 106.5 ±25.9 minutes. The mean estimated   intraoperative    blood   loss   was

276.5 ±175.7 ml. Operative  data are shown

in Table (3).

The  mean  period  until  passage  of flatus was   2  ±1.3   days.   The  patients   resumed oral food intake in 3.1 ±1.6 days and were discharged  from  the  hospital  in  4.3  ±1.4 days. 6 patients (10.5%) had post-operative complications in their hospital stay, 4 (7.2%) had wound infection (the midline incision) which was treated by dressing and antibiotics, and 2 (3.5%) had prolonged ileus which was managed conservatively (all were converted cases).  No mortality  was recorded  intra  or post operatively. The postoperative data are shown in Tables (4,5).

We divided the cases for 10 case groups (5 (10) cases and 1 (7) cases groups). Then we analyzed  the  preoperative  parameters  (age, sex,   surgical   indication   for   splenectomy, ASA score, other comorbidities, size of the longitudinal  access of  the spleen  and  body mass  index)  to  make  sure  that  they  don't affect the outcome measures. The analysis showed that there is no significant difference between the groups regarding preoperative parameters.

Then  the  outcome   measures  (operative

time, estimated intraoperative  blood loss, the need for conversion to open splenectomy, postoperative  complications,  period of ileus and hospital  stay)  were calculated  for each of the groups and evaluated for statistical significance. Summary of outcome measures in each group is shown in Table (6).

When we analyzed these parameters. We found  that the  mean operative  times  in the

3rd, 4th, 5th and 6th groups were significantly

shorter than the  1st and 2nd groups,  with  a clear trend towards decrease operative time with each group. Operative time started to reach a plateau in the final 27 patients, which

was  between  40-45minutes  faster  than  that

Am-ShamsJSurg2014; 7(2):281-288

seen in the first 20 patients.

There was a trend toward decreased blood loss in the latter groups (Jid, 4th, 5th and 6th), and the differences between them and the 1st

2 groups were statistically significant.

Although that there was a trend of high postoperative complications and conversion rate in the 1st group in relation to the  other groups, a statistically significant difference between groups couldn't  be found in our trial. Similarly, although there was a trend towards decreased period of ileus with the consecutive groups, a statistically significant difference couldn't  be shown.

Regarding the hospital stay, a statistically significant difference was found between the consecutive groups.

These  results  showed  that  the  outcome

measures were seen to improve with the advancement of the experience with a plateau reached after 20-30 cases of laparoscopic splenectomy.

Discussion:

Since its introduction, laparoscopic splenectomy had become the golden standard for elective splenectomy, as it is feasible, safe and provides many advantages to the patients in  comparison   to  open   splenectomy,   and the growing experience and the advances in equipment  had made it feasible in situations that were thought to be contraindications  in the past.3,4

Mastering this procedure to achieve its benefits requires advanced laparoscopic surgical skills and overcoming the learning curve associated with the procedure.10 The learning curve for advanced laparoscopic procedures  has  been  described  in  the literature     (eg,    Nissen     fundoplication,11 colon  resection,12  Roux-en-Y  gastric bypass13 and splenectomy14). Our study was undertaken to define the learning curve for laparoscopic  splenectomy  in our institution. We  assumed   that   achieving   the   learning curve  will  be  manifested   by  a  plateau  in certain outcome measures (operative time, estimated    intraoperative    blood   loss,   the need for conversion to open splenectomy, postoperative  complications,  period  of ileus

and hospital stay).

We first performed an analysis of preoperative   parameters   to   eliminate   any bias  in the  study,  as  it  is well  known  that these factors (indication, splenic size, dense adhesions and portal hypertension)  affect the outcome measures.3,5,6,7,8

Operative times were significantly reduced with  increasing  experience.  We found  that the  mean operative  times in the 3rd, 4th, 5th and  6th  groups   were  significantly   shorter than the 1st and 2nd groups, with a clear trend towards  a  decrease  in  operative  time  with each group.  Operative time started to reach a plateau in the final 27 patients, which was between 40-45minutes faster than that seen in the first 20 patients. As we didn't  modify the technique  or instruments,  this  improvement is  mostly  due to  increased  familiarity  with the operation and the ability to provide better exposure and to dissect more expeditiously. Others have also reported a similar decrease in operative times, although with smaller numbers.15

There was a trend toward decreased blood loss in the latter groups (3rd, 4th, 5th and 6th), and the differences between them and the 1st

2 groups were statistically significant. Blood loss decreased with time primarily because of improved technical  ability to accomplish the operation.

Complications in this study were few and

were mostly spaced out over the entire series of patients.  Although that there was a trend of high postoperative complications and conversion  rate  in the  1st group  in relation to the other groups, a statistically significant difference between groups couldn't  be found in our study.

Similarly,   although   there   was   a  trend

towards decreased period of ileus with the consecutive  groups, a statistically significant difference   couldn't   be   shown.   Regarding the hospital stay, a statistically significant difference was found between the consecutive groups.

As noted, outcomes improved rapidly with

the first 20-30  patients. The learning curve flattens   and   outcome   parameters   become more consistent after the first 30 patients. This

Figure (1): A diagram showing surgical team position and port position A: 12 mm port at umbilicus, B:  12 mm  port at midclaviular line just above umbilical level, C: 5 mm port below xiphisternum, D: 5 mm port at anterior axillary line below costal margin.

Figure (2): An  intraoperative picture showing: A:  dissection of gastrosplenic ligament, B: dissection of the inferior splenic attachments.

Figure (3): An  intraoperative picture showing: A: application of the EndoGIA to the hilum, B: after transection of the hilum.

Oper-..tive time trend                                    ln1raoperative bk>od loss tr

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Figure (4):Graphic representation of different outcome measures trend. Table (1): Showing the indication of splenectomy in the study group.

Table (2): Preoperative data.

Table (3): Showing operative data.

Tables (4, 5): Showing postoperative  data.

Table (6): Showing outcome parameters for each group.

is  consistent  with  many  studies  that  stated that the learning curve for the procedure is 20 cases8,14 or 20-25.6

Interestingly, the significant improvement in operative time did not correspond with a significant  improvement  some  of the  other

outcomes  measures   including   conversion to  open  splenectomy, postoperative complications,  period  of   ileus.   One explanation for this may be the small statistical power when  comparing the sequential groups of  10 patients. Another possible explanation for  this  finding may  be that  laparoscopic splenectomy can be safely performed early in the  learning curve  by  surgeons who  possess advanced laparoscopic skills. This  trend was reported previously in the  literature.8

Conclusion :

Laparoscopic splenectomy can be done safely by experienced laparoscopic surgeons. A learning curve  for  mastering the procedure is 20-30 cases,  after  which the  outcome parameters nearly reach a plateau.

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