We reviewed the primary LH videos of 13 future recurrence and 28 control lesions. The basic characteristics, including the surgeon’s degree of experience, were not significantly different between the groups (Table 2). The 12-item questionnaire completed for each of the 41 videos demonstrated good internal consistency among the reviewers (Cronbach’s α co-efficient = 0.816).
Table 2. Characteristics of future recurrent and control lesions used for the video reviews
|
Future recurrent
(n = 13)
|
Control
(n = 28)
|
p-value
|
Gender, male:female
|
13:0
|
28:0
|
|
Age (years)
|
63.8 ± 11.8
|
62.5 ± 15.0
|
0.847*
|
Operation time (min)
|
117 (65–158)
|
122 (60–324)
|
0.294†
|
Laterality, Lt.: Rt.
|
5:8
|
10:18
|
1.000¶
|
JHS type, I: II
|
7:6
|
16:12
|
1.000¶
|
JHS type, Primary: Recurrence
|
10:3
|
26:2
|
0.304¶
|
Surgeon’s experience (cases)
|
12.5 (1–72)
|
10.0 (1–73)
|
0.897†
|
*Student’s t-test, †Mann-Whitney U Test, ¶ Fisher’s exact test.
JHS: Japan Hernia Society.
Division into two periods: Before and after the policy change
To determine how entire lesions were grouped according to their rating differences, the lesions were rearranged using hierarchical clustering (Figure 2). There were two main branches on the y-axis. The upper branch comprised lesions 17 to 118, except for lesion 167, while the lower branch comprised lesions 136 to 528, except for lesion 119. This grouping was mostly divided by the period of operation, yet was not based on whether the lesions were future recurrent or not. Our surgical policy change occurred between lesions 136 and 161, it was close to a boundary of the above grouping between lesions 118 and 136. We therefore subsequently analyzed the data for the two periods separately. In the earlier period, 175 (58%) of the 300 questions were rated less than or equal to 0.4, indicating unsatisfactory ratings were predominant. Conversely, 143 (79%) of the 180 questions were rated greater than or equal to 0.6 during the later period, indicating generally satisfactory ratings and that the policy looked adhered to thoroughly.
Surgical techniques intraoperatively predict hernia recurrence after TAPP repair
To determine which techniques could predict hernia recurrence after TAPP repair, we assessed the differences of the ratings in each item between future recurrences and controls. In the earlier period, no items were significantly different between the future recurrences and controls in a univariate analysis (Supplemental Table 2). As unsatisfactory ratings were predominant in the controls, no techniques could predict future recurrence in the period. In the later period, we rearranged the heat map table according to rating values in order to make the differences between future recurrences and controls in each item conspicuous (Figure 3). Regarding the ratings of the posterior prosthesis overlap (item J), three of the five recurrent lesions were rated 0.4 to 0.6, whereas eight of the 10 control lesions were rated 1.0, with a significant difference in a univariate analysis (p = 0.019). The probability of recurrence was higher when the reviewers agreed the posterior overlap was insufficient.
Regarding the ratings of prosthesis folding or crinkling posteriorly (item K), there was no significant difference between the two groups. However, unsatisfactory ratings of 0.0 were observed in three of the five recurrent lesions and, conversely, in none of the controls. The strong agreement of an unsatisfactory rating on the item among the reviewers, indicating an apparent technical error. Regarding the ratings of prosthesis fixation (item L), four of the five future recurrent lesions were rated less than 0.40, compared to only one of the 10 controls receiving a similar rating. The ratings in the future recurrences tended to be lower than the controls, although the difference was insignificant (p = 0.060).
Differences in recurrence rates and their forms before and after the policy change
To appreciate how such surgical technique errors affected hernia recurrence, we investigated the recurrence rates for each period and each type of recurrent hernia. Due to general observations of unsatisfactory ratings during the earlier period and satisfactory ratings during the later period, these ratings were regarded as examples of all TAPP repairs for each period. When we inspected the recurrence rates for the two periods, the recurrence rate dropped drastically from 6.2% (10/161) during the earlier period to 0.7% (5/678) in the later period (chi-squared test, p < 0.001). A gross satisfactory rating in the later period should affected to enlargement of the prosthesis size. The average size of the prosthesis in the later period was 13.3 by 9.4 cm, while the earlier period’s average was 9.9 by 7.2 cm, indicating a significantly difference (Student’s t-test, p < 0.001). This indicates that fully covering the MPO resulted in the usage of a larger prosthesis, which helped reduce the recurrence rate.
We explored the differences in the types of hernia recurrence between the two periods. Both Type I and II recurrences were observed in the earlier period, where six of the nine cases relapsed with Type II, while three relapsed with Type I (Table 3). There were three cases in which the hernia types changed from Type I to II (or Type II to I) when the hernias relapsed. In contrast, the five cases that relapsed in the later period were all primary and recurrent Type I (p < 0.006). Furthermore, when reviewing the reoperation videos in the five observed later period cases, the meshes shifted anteriorly and/or medially to the hernia orifices, but not posteriorly. The sizes of the orifices were more than 30 mm in the three most recent cases, which were all classified as JHS Type I-3. Consequently, fully covering the MPO effectively reduced Type II recurrence. Even when fully covering the MPO, insufficient posterior overlap of the prosthesis would lead to Type I hernia recurrence.
Table 3. Type of recurrence according to the date of primary LH
JHS Classification
|
|
Date of the primary LH
|
p value*
|
Primary LH
|
Recurrence
|
|
In the earlier period
(n = 9) a
|
In the latter period
(n = 5)
|
II
|
II
|
|
5
|
0
|
0.006
|
I
|
II
|
|
1
|
0
|
II
|
I
|
|
2
|
0
|
I
|
I
|
|
1
|
5
|
a Case 103 was added to the data, *Fisher-Freeman-Halton exact test.
LH: laparoscopic hernioplasty, JHS: Japan Hernia Society.