Affiliations
doi: 10.29271/jcpsppg.2025.01.33ABSTRACT
Objective: To compare the outcomes of botulinum toxin injection and lateral internal sphincterotomy for the treatment of chronic anal fissure.
Study Design: Quasi-experimental study.
Place and Duration of the Study: Department of General Surgery, Combined Military Hospital, Rawalpindi, Pakistan, from August 2024 to January 2025.
Methodology: A total of 84 patients with chronic anal fissure were included. Patients were allocated either to group BT (Botulinum toxin) or group LIS (lateral internal sphincterotomy). Outcomes, including pain resolution after 24 hours of surgery, healing, post-procedural infection, and faecal incontinence, were analysed and compared between groups using the Chi-square test.
Results: In this study, 84 patients were included, divided into two groups. Median age was 41.00 (19.75) years. There were 62 (73.81%) males and 22 (26.19%) females. The median body mass index (BMI) was 31.60 (5.70) kg/m2. Median duration of fissure was 9.00 (4.00) weeks. Median pre-procedural pain score was 7.00 (1.75). In Group BT (n = 42), complete healing after three months of the procedure was achieved in 31 (73.81%) patients, while in Group LIS (n = 42), it was achieved in 40 (95.24%) patients (p = 0.007).
Conclusion: LIS provides a significantly higher healing rate compared to the injection of botulinum toxin given intra-sphincterically.
Key Words: Anal fissure, Assessment, Botulinum toxin, Outcome, Sphincterotomy.
INTRODUCTION
One common painful condition related to the anal region is the anal fissure which results from a break in the normal continuity of the anal skin distal to dentate line.1 In most instances, it is an acute condition and can affect the population of any age group; however, in certain circumstances, it becomes chronic, causing recurring symptoms, making it a difficult condition to treat.2 Several aetiological processes can lead to development of this condition such as constipation (the most common one), fibre-poor diet, tuberculosis (TB), inflammatory bowel disease (IBD), and history of any malignancy or intervention of the anal region.3
Despite several known causes of this condition, its exact pathophysiology remains unclear. It has been observed that although most cases of acute fissures related to trauma heal, others do not.
When they remain persistent for more than six weeks, they are labelled as chronic fissures.4 Other than differences in duration, chronic fissures are phenotypically different from acute fissures as these are deeper, wider, and contain granulation tissue at their base. In contrast, acute fissures are linear and have clear margins.5 Management of this condition is highly important since studies have shown that this condition significantly reduces the overall life quality of the ailing patients, which is drastically improved upon successful treatment.6
In case of chronic anal fissures, the main goal of treatment is to relieve the symptoms of patient by lowering the increased tone of the anal sphincter which is achieved by a variety of interventions, from minimally invasive to invasive operative procedures. Some of these non-operative interventions include physical therapy of the pelvic floor, topical calcium channel blockers, and glyceryl trinitrate.7 Another such intervention is intra-sphincteric injection of botulinum toxin, which is hypothesised to be one of the most useful interventions in this regard.6 However, when it comes to comparison of its effectiveness with the surgical management through lateral internal sphincterotomy (LIS), evidence is variable at best with some of the studies reporting it to provide either equally comparable or significantly higher healing rate as compared to LIS while others reporting it to be significantly inferior to LIS.8 To answer this major discrepancy in previous literature, present study is being conducted to compare the outcomes of botulinum toxin injection and LIS for the treatment of chronic anal fissures.
METHODOLOGY
This quasi-experimental study was conducted at the Department of General Surgery, Combined Military Hospital, Rawalpindi, Pakistan, from August 2024 to January 2025, after getting approval from the Institutional Ethical Committee (Ref No: 822, Dated 31-03-2024). Sample size calculation was performed using the World Health Organization (WHO) sample size calculator using the following formula:
Sample size calculation was performed by using the level of significance of 5%, power of 80%, and anticipated frequencies of healing in BT and LIS groups of 90.3% and 65.1%, respectively.9 This gave a sample size of 84 (42 in each group). Study sample was selected by using non-probability consecutive sampling technique.
Both male and female adult patients who presented with chronic anal fissure were included. It was defined based on the duration of its persistence for six weeks or more. Patients who had a history of intestinal TB, IBD, uncontrolled diabetes and hypertension, history of surgery of the anal region, malignancy of the anal canal, and pre-existing faecal incontinence due to any reason, were excluded.
After approval of the study proposal and obtaining informed consent from the patients, all patients presenting at the surgical outdoor department and meeting all the inclusion criteria were included in the study. Baseline characteristics including age, gender, body mass index (BMI), duration of anal fissure, and pre-procedural pain score were documented. To assess pain, a standard numeric pain scale was used that gauged the pain from numbers 0 to 10, with higher numbers corresponding with increasing pain severity. After this, group allocation was performed according to the choice of the patient. All patients were briefed regarding the pros and cons of both procedures and were asked for their choice. In case of completion of the number of participants in one group before the other, remaining patients were only offered the procedure for which recruitment was required to complete the number of participants per group. Group BT was treated with intra-sphincteric injection of 100 units of botulinum toxin, given within the internal anal sphincter in the midline either anteriorly or posteriorly and this choice was guided by the location of the fissure. Group LIS was treated by performing LIS under regional anaesthesia following the standardised surgical steps. Both the procedures were performed by the same surgical team with each member having at least three years of experience in anal surgical interventions to avoid operator bias.
Patients in both groups received the same pre-procedure, intra-procedure, and post-procedure ancillary management to avoid any impact on the outcome of either procedures. After the procedure, patients were admitted for one day for monitoring. After 24 hours of procedure, patients in either groups were assessed for resolution of pain (defined as the numeric pain scale score <2). Pain assessment was performed by the surgeon who was blind to the procedure being performed. After this, patients were discharged home with medications as per hospital protocol and a follow-up plan of visiting each month for 3 months after surgery. At completion of three months, patients were assessed for healing of the fissure which was defined by a complete absence of pain in the anal region and normal physical examination of the anus. During the follow-up visit, any event of surgical site infection (SSI) and faecal incontinence was also documented. Assessor of outcomes was kept blind to the type of intervention provided. Patient selection and assessment process is demonstrated in Figure 1 using a CONSORT patient flow diagram.10
Statistical analysis of collected data was performed using the Statistical Package for Social Sciences (SPSS) software version 20. Normality of data was assessed using the Shapiro-Wilk test. Based on this, age, BMI, duration of anal fissure, and pre-procedural pain score were found to be non-normally distributed and were represented using median ± interquartile range (IQR). These values were compared between groups using the Mann-Whitney U test. Frequencies and percentages were used for categorical variables (gender, resolution of pain 24 hours after procedure, healing at 3 months, post-procedural infection, and faecal incontinence). To compare outcomes between groups, the chi-square test was used as a test of significance. A p-value of ≤0.05 was considered statistically significant.
Figure 1: CONSORT patient flow diagram.
Table I: Comparison of baseline characteristics among groups (n = 84).
|
Parameters |
Group BT (n = 42) |
Group LIS (n = 42) |
p-values |
|
Median age |
41.00 (17.25) years |
40.50 (20.25) years |
0.921* |
|
Gender Male Female |
27 (64.29%) 15 (35.71%) |
35 (83.33%) 7 (16.67%) |
0.047† |
|
Median BMI |
31.65 (5.70) kg/m2 |
31.60 (6.60) kg/m2 |
0.726* |
|
Median duration of anal fissure |
9.00 (2.25) weeks |
10.00 (5.00) weeks |
0.056* |
|
Median pre-procedure pain score |
7.00 (2.00) |
7.00 (1.25) |
0.742* |
|
*Mann-Whitney U test. †Chi-square test. |
|||
Table II: Comparison of outcomes between the two procedures (n = 84).
|
Outcomes |
Group BT (n = 42) |
Group LIS (n = 42) |
p-values |
|
Resolution of pain at 24 hours |
39 (92.86%) |
35 (83.33%) |
0.178† |
|
Post-procedural infection |
1 (2.38%) |
3 (7.14%) |
0.608† |
|
Complaint of faecal incontinence |
2 (4.76%) |
5 (9.52%) |
0.430† |
|
Complete healing at 3 months |
31 (73.81%) |
40 (95.24%) |
0.007† |
|
†Chi-square test. |
|||
RESULTS
In this study, 84 patients were included. Median age was 41.00 (19.75) years. There were 62 (73.81%) male and 22 (26.19%) female patients. Median BMI was 31.60 (5.70) kg/m2. Median duration of having a fissure was 9.00 (4.00) weeks. Median pre-procedure pain score was 7.00 (1.75). Baseline characteristics of patients of both groups are compared in Table I.
In Group BT, pain resolution at 24 hours after the procedure was achieved in 39 (92.86%) patients, while in Group LIS, it was achieved in 35 (83.33%) patients (p = 0.178). In Group BT, an event of post-procedural infection during three months follow-up period occurred in 1 (2.38%) patient, while in Group LIS, it occurred in 3 (7.14%) patients (p = 0.608). In Group BT, complaint of faecal incontinence during three months follow-up period after the procedure was reported by 2 (4.76%) patients, while in Group LIS, it was reported by 5 (9.52%) patients (p = 0.430). In Group BT, complete healing after three months of procedure was achieved in 31 (73.81%) patients, while in Group LIS, it was achieved in 40 (95.24%) patients (p = 0.007). Comparison of these outcomes is given in Table II.
DISCUSSION
Anal fissures are a cause of major distress among the ailing patients owing to their painful nature and the association of a social stigma that does not allow sufferers to express their complaint freely without hesitation.11 Since it is a difficult-to-treat and recurring condition, it is essential to explore every modality of treatment and intervention that can help in the effective eradication of this condition. The present study focused on comparing the outcomes of two such treatment options that have been considered to be useful in this regard.
In the present study, patients who presented with chronic anal fissure were aged between 23 and 57 years. Similar to this trend, studies conducted by Rahbar et al. and Rahman et al. found that the patients with anal fissure primarily fell within this age range with highest frequency being noted in those aged between 31 and 40 years.12,13 Upon analysis of gender distribution, a clear male predominance was noted, with males constituting 73.81% of the total study population. Similar to this, Sakr et al. reported a male predominance in this regard, with males constituting 58% of the fissure patients.14 Contrarily, Bara et al. found that majority of sufferers of this condition were females that made-up 53.8% of the patients suffering from anal fissure.15 Another important aspect of the present study was the high BMI, falling in the range of obesity, among patients with this condition. This can be explained by higher chances of obese patients having chronic constipation and other gastro-intestinal conditions, making them more prone to develop this disease.16
In the present study, various outcomes of these two proce-dures i.e., botulinum toxin (Botox) and LIS were explored in managing patients who presented with chronic anal fissure. The earliest parameter which was assessed at 24 hours after performing the intervention was the resolution of pain, which was observed to be statistically similar between the two groups (p = 0.178). Similar to this trend, a study was conducted by Saleem et al.17 who found that no statistical difference existed between these two procedures based on pain resolution after a day of procedure (p = 0.109), but this rate of pain resolution was high at this point in time in both the groups.
Regarding the safety of the procedures, two parameters were studied in the present study, including post-procedural infection and faecal incontinence, and their occurrence was monitored during the whole three-month follow-up till the final assessment of the patients. In this instance, it was found that both procedures were equally safe based on the frequency of post-procedural infection (p = 0.608) and complaint of faecal incontinence (p = 0.430). Similar to these findings, there are multiple studies have been conducted in this regard by Saleem et al.,17 De Robles et al.18 and Rashad et al.,19 all of whom have reported similar results showing that both techniques are equally safe based on the frequency of these complications with no statistical difference observed between them.
Finally, the main outcome measure that was compared for these two interventions was the rate of complete healing and it was found that the rate of complete healing at three months after the procedure was 95.24% in Group LIS which was significantly higher as compared to Group BT in which the rate was 73.81% (p = 0.007). Compared to the healing rate of 73.81% with Botox reported in the present study, Brisinda et al.20 reported that the healing rate of fissure treated with botulinum toxin was 94.3%, showing a major difference; however, this difference can be attributed to the difference in the situation between the two studies. In their study, patients had undergone prior LIS and subsequently were treated with botulinum toxin, while in the present study, patients were naive to either therapy before their inclusion in the present study.
Similar to the trend of significantly better healing rates with LIS, a study conducted by El-Fotouh Mohamed et al.21 and Ahmed et al.22 reported that the healing rate of anal fissures treated with LIS was significantly higher as compared to those treated with botulinum toxin (p <0.05). Contrarily, a study was conducted by Minhas et al.,9 who reported opposite results with a significantly higher rate of healing being reported among those treated with botulinum toxin rather than LIS (p <0.001). In contrast to both these extre-mes, studies conducted by Saleem et al.17 and Zngana and Hiwa.23 reported both these interventions to be equally effective without any significant differences between the two interventions based on the rate of complete healing of chronic anal fissure (p >0.05).
The present study demonstrates that healing rates are higher at three months with LIS, but both interventions are equally safe. Therefore, owing to the ease of performance and less invasiveness, it is recommended that patients with chronic anal fissure should initially be treated with botulinum toxin therapy and only in cases of failure, LIS should be performed. There were no limitations of the present study except for a shorter follow-up period, due to which, the recurrence rate could not be assessed.
CONCLUSION
In conclusion, LIS provides significantly higher rates of complete healing compared to injection of botulinum toxin given intra-sphincterically. However, both the procedures are equally safe since the rate of resolution of pain at 24 hours after procedure and the complaints of faecal incontinence and infection were statistically similar after both the procedures.
ETHICAL APPROVAL:
Ethical approval was obtained from the Institutional Ethics Committee of the Combined Military Hospital, Rawalpindi, Pakistan (Ref No: 822, Dated; 31-03-2024).
COMPETING INTEREST:
The authors declared no conflict of interest.
PATIENTS’ CONSENT:
Written informed consent was obtained from the patients.
AUTHORS’ CONTRIBUTION:
SSS: Conception, study design, acquisition of the data, and manuscript writing.
SMH, MAM, BS: Analysis, interpretation, and acquisition of the data.
DN, MJA: Analysis, interpretation, critical review, and acqui-sition of the data.
All authors approved the final version of the manuscript to be published.
REFERENCES