Non-surgical magnetic-electrical biofeedback improves anterior resection syndrome after sphincter-preserving surgery for low rectal cancer

Abstract

BACKGROUND

Sphincter-preserving surgery is a common procedure for rectal cancer, but anterior resection syndrome (ARS) remains a frequent complication.

AIM

To evaluate the efficacy of combined magnetic-electrical biofeedback therapy in patients with ARS after sphincter-preserving surgery for low rectal cancer.

METHODS

Sixty patients with ARS following sphincter-preserving surgery for low rectal cancer admitted to our hospital between August 2024 to March 2026, were selected. Based on the chronological order of surgery, the patients were divided into control group and (n = 30) receiving conventional intervention or a study group (n = 30) receiving magnetic-electrical biofeedback therapy. Bowel function indicators, Low ARS (LARS) scores and Memorial Sloan Kettering Cancer Center Bowel Function Instrument (MSKCC-BFI) scores were assessed before, 1 month after, and 3 months after intervention. Anal pressure indicators, including anal resting pressure and maximum squeeze pressure, were evaluated before and after the intervention. Anorectal function indicators, including first rectal sensation volume, maximum tolerated volume, and rectal compliance, were compared before and after the intervention. The clinical efficacy rates were also calculated for both groups.

RESULTS

Baseline bowel function indicators, LARS scores, and MSKCC-BFI scores (P > 0.05) did not differ significantly between groups. After treatment, the study group showed fewer daily bowel movements, lower fecal incontinence frequency scores, lower LARS scores, and higher MSKCC-BFI scores than the control group (all P < 0.05). No significant differences were observed in anal pressure or anorectal function indicators before the intervention (P > 0.05). Anal resting pressure, maximum squeeze pressure, as first rectal sensation volume, maximum tolerated volume, and rectal compliance were also significantly higher in the study group than the control group (P < 0.05). The total effective rate was 96.67% (29/30) significantly higher in the study group than 73.33% (22/30) in the control group [96.67% (29/30) vs 73.33% (22/30), P < 0.05].

CONCLUSION

Combined intervention using magnetic-electrical biofeedback demonstrated significant efficacy in patients with ARS after sphincter-preserving surgery for low rectal cancer. It facilitates the synergistic recovery of rectal and anal canal functions, plays a positive role in improving patients’ bowel movements and anorectal function, and promotes enhanced clinical outcomes.

Key Words: Magnetic-electrical biofeedback therapy; Low rectal cancer; Sphincter-preserving surgery; Anterior resection syndrome; Anorectal function

Core Tip: Anterior resection syndrome remains one of the most challenging functional complications after sphincter-preserving surgery for low rectal cancer, substantially affecting patients' quality of life. This study demonstrates that combined magnetic-electrical biofeedback therapy significantly improves bowel function, anal sphincter function, anorectal physiological parameters, and patient-reported bowel function compared with conventional rehabilitation alone. The combined intervention achieved a higher overall clinical response rate and promoted coordinated recovery of rectal and anal functions, suggesting that it is a safe, effective, and promising rehabilitation strategy for postoperative anterior resection syndrome management.

INTRODUCTION

Lower rectal cancer is a common malignancy of the digestive tract. Sphincter-preserving surgery has become a widely adopted treatment because it retains the patient’s anal defecation function and improves postoperative quality of life[1]. Multiple clinical reports indicate that anterior resection syndrome (ARS) tends to occur after sphincter-preserving surgery for rectal cancer. The core manifestations in patients include increased defecation frequency, fecal incontinence, and fecal urgency. Some patients also experience abnormal rectal sensation and decreased anal sphincter function, which severely reduces their quality of life, making it a current clinical challenge in rehabilitation following sphincter-preserving surgery for low rectal cancer[2,3]. The current conventional clinical interventions for ARS primarily include dietary guidance[4], regular bowel habit training[5], and Kegel exercises[6]. Although these approaches can alleviate symptoms to some extent, they rely heavily on patients’ autonomous perception and motor control, and are prone to issues such as compensatory pelvic floor muscle contractions and insufficient training precision. They lack directness and specificity in improving the rectal sensory function and anal sphincter pressure, resulting in insignificant symptom relief and limited long-term quality of life improvement in some patients[7]. Therefore, identifying more precise and effective ARS intervention strategies has become a research hotspot in the field of clinical postoperative rehabilitation.

Magnetic-electrical biofeedback is a rehabilitation approach that combines physical stimulation with functional training. By integrating the dual intervention advantages of magnetic stimulation and electrical biofeedback, overcoming the limitations of traditional single-rehabilitation methods[8]. Magnetoelectric biofeedback technology has multiple functions such as nerve repair and muscle strength regulation. This is in line with the core pathogenesis of ARS and has the advantages of noninvasive safety and strong repeatability. This demonstrated good application prospects in the field of pelvic floor function rehabilitation.

Magnetic-electrical biofeedback technology, as a rehabilitation approach that combines physical stimulation with functional training, integrates the dual intervention advantages of magnetic stimulation and electrical biofeedback, breaking through the limitations of traditional single rehabilitation methods. Magnetoelectric biofeedback technology has multiple functions such as nerve repair and muscle strength regulation. It is in line with the core pathogenesis of ARS and has the advantages of non-invasive safety and strong repeatability. It shows a good application prospect in the field of pelvic floor function rehabilitation. However, relatively little research has been conducted on the application of this technology in patients with ARS after sphincter-preserving surgery for lower rectal cancer, and its effects on the core symptoms of ARS, rectoanal function, and patient quality of life have not yet been systematically validated. Therefore, this study considered patients with ARS after sphincter-preserving surgery for lower rectal cancer as research subjects to explore the intervention effects of combined magnetic-electrical biofeedback therapy.

MATERIALS AND METHODS

General information

Sixty patients with ARS after sphincter-preserving surgery for low rectal cancer, admitted to our hospital between August 2024 to March 2026. The inclusion criteria include: (1) Low rectal adenocarcinoma confirmed by histopathological examination[9]; (2) Lower tumor margin ≤ 10 cm from the anal verge; (3) Laparoscopic or open low anterior resection or other sphincter-preserving surgeries, with negative surgical margins and no abdominal stoma; and (4) normal cognitive and communication abilities, allowing participation in magnetic-electrical biofeedback training and outcome assessments. The exclusion criteria include: (1) Primary malignant tumors in other sites; (2) Previous anorectal surgery or organic injury to the anal sphincter; (3) inflammatory bowel disease, irritable bowel syndrome, chronic diarrhea, constipation, or intestinal infection; (4) inability to tolerate biofeedback training; and (5) Contraindications to magnetic-electrical biofeedback therapy. Sixty patients were divided into the control group and the study group according to the sequence of operation time. No significant difference was observed in the baseline data between the two groups (P > 0.05), and they could be compared. See Table 1.

Table 1 Baseline data of two groups, n (%)/mean ± SD.

Group	Gender		Age (years)	Distance (cm) from the tumor to the anal margin	Clinical staging
	Male	Female			Phase II	Phase III
Control group (n = 30)	19 (63.33)	11 (36.67)	61.17 ± 3.05	7.15 ± 0.63	23 (76.67)	7 (23.33)
Study group (n = 30)	18 (60.00)	12 (40.00)	60.47 ± 3.36	7.21 ± 0.59	22 (73.33)	8 (26.67)
χ2/t	0.071		0.845	0.381	0.089
P value	0.791		0.402	0.705	0.765

Methods

The control group received conventional interventions focused on intestinal function regulation and health guidance. Postoperatively, the patients were informed about the pathogenesis of ARS and the patterns of postoperative intestinal function recovery using one-on-one explanations combined with video demonstrations. A personalized diet plan was developed to guide the patients to consume high-fiber, easily digestible foods, with daily water intake controlled at 1500-2000 mL, avoiding spiky, greasy, and gas-producing foods. Regular bowel habit training was implemented as follows: Attempting defecation upon waking or 30 minutes after meals daily and maintaining a seated posture during defecation, with each session not exceeding 10 minutes. Abdominal clockwise massage can be used for assistance, if necessary. Patients were guided daily to perform Kegel exercises, simulating the actions of holding back stool or gas to contract the anal sphincter, holding the contraction for 5-10 seconds, and relaxing for 5-10 seconds, with 10-15 repetitions per set, three sets per day. The contraction duration and number of sets were gradually increased based on patient tolerance, avoiding excessive training and muscle fatigue.

The study group received a combined magnetic-electrical biofeedback intervention in addition to the control group’s regimen.

Biostimulation feedback intervention: The instrument used was a bioelectric feedback stimulator (model: SA9805; Nanjing Weisi Medical Technology Co., Ltd., Jiangsu Province, China). Patients were assisted in a semi-recumbent position and exposed to the treatment and monitoring areas (abdomen and anus). Appropriate sizes of rectal electrodes and electrode patches were selected based on the treatment area. The surface of the rectal electrode was evenly coated with a lubricating conductive gel and gently inserted into the anus (the electrode head was completely inside the anal opening). The electrode patches were adhered to the abdomen. The initial parameters were set at low intensity, with electrical stimulation frequency (10-20 Hz) gradually adjusted based on tolerance, aiming for a level at which the patient consciously felt anal sphincter contraction without pain. During treatment, the patients’ facial expressions, physical reactions, and device data (such as electromyography values and stimulation intensity) were monitored, with attention paid to inquiring about their sensations. Parameters and electrode positions were adjusted to prevent burning or stinging. Electrical stimulation can enhance pelvic floor function, promote local tissue blood circulation, and repair damaged or abnormal floor muscles.

Biofeedback Training Intervention: Visual (screen waveforms) or auditory (verbal prompts) feedback was provided. Patients control feedback signals by contracting and relaxing their muscles. Targeted active training (relaxation, coordination, and strength training) was conducted, maintaining contraction for 10 seconds and relaxation for 10 seconds. Based on feedback signals, patients were guided to precisely contract and relax the anal sphincter, correct improper contraction actions, and avoid compensatory contractions of the abdominal or thigh muscles. This study aimed to reestablish the correct motor pattern for defecation using pelvic floor muscle relaxation combined with increased intra-abdominal pressure. Biofeedback uses simulated auditory or visual signals to provide feedback on normal and abnormal pelvic floor muscle activity states, helping patients or therapists understand the correctness of pelvic floor muscle exercises, thereby achieving correct and more effective pelvic floor muscle training.

Magnetic Stimulation Intervention: A magnetic stimulator was used (model: Magneuro60F; Nanjing Weisi Medical Technology Co., Ltd., Jiangsu Province, China). The patients were assisted in a sitting or prone position according to the treatment plan, and the magnetic field intensity was adjusted. In the sitting position, the intensity was adjusted until the patient felt a bellows-like sensation of movement in the buttocks. The coil was positioned over the sacral nerve with the patient in the prone position. The magnetic induction intensity ranged from 0.5-1 T, gradually adjusted based on tolerance. The magnetic stimulation intensity should not be too high and should be adjusted to a level where the stimulation sensation is noticeable and comfortable. Magnetic stimulation utilizes a time-varying magnetic field to induce currents within tissues, regulate the excitability of neuromuscular tissues, promote the remodeling of damaged nerves, increase blood circulation, and enhance the strength of the pelvic floor and local tissue muscles, thereby treating pelvic floor dysfunction disorders and other related conditions.

The combined magnetic-electrical biofeedback intervention was conducted three to five times per week. Each session lasted 50 minutes (30 minutes for biostimulation feedback therapy and 20 minutes for magnetic stimulation therapy). Patients were instructed to simultaneously perform biofeedback reinforcement training at home to consolidate the intervention effects. The combined magnetic-electrical biofeedback therapy for anorectal and pelvic floor diseases aims to help patients achieve better therapeutic outcomes and improve quality of life through the combination of multiple technologies. Both groups were followed up for 3 months via online and outpatient review methods.

Observation indicators

Indicators related to bowel movement: The frequency of bowel movements was recorded in both groups before and after the intervention (three months). Simultaneously, the fecal incontinence frequency scores were assessed before and after the intervention. This score includes evaluations across five dimensions: Incontinence to liquid stool, incontinence to solid stool, incontinence to gas, lifestyle alterations, and the need to wear pads. Each dimension is scored from 0 to 4 based on severity and frequency, with a total possible score of 20 points. Higher scores indicated a higher frequency of incontinence.

Low ARS score: The severity of bowel dysfunction in both groups was assessed using the LARS score before the intervention and 1 month and 3 months after the intervention. This scale assesses fecal urgency, incontinence, frequency, evacuation difficulties, and painful defecation. Each item is rated using a Likert 4-point scale (0 to 3) based on symptom frequency or severity. Symptom frequency scoring criteria: Never counted as 0 points, 1 point for < 1 occurrence per week, 2 points for ≥ 1 occurrence per week but < 1 occurrence per day, and 3 points for ≥ 1 occurrence per day; A higher score indicates more severe bowel dysfunction.

Memorial Sloan Kettering Cancer Center Bowel Function Instrument score: Quality of life related to bowel function was assessed in both groups using the Memorial Sloan Kettering Cancer Center Bowel Function Instrument (MSKCC-BFI)[10] score before and 1 month and 3 months after the intervention. The instrument comprises three dimensions (diet-related symptoms, fecal urgency/soiling of undergarments, and stool frequency) and four independent questions, with a total of 18 items. The total score ranged from 0 to 90, with a higher score indicating a better quality of life related to bowel function.

Anal pressure indicators: Before including anal resting pressure (ARP) and maximum squeeze pressure (MSP), were measured before and after the intervention (3 months) using anorectal manometry equipment (model IGJ-D3; Hefei Aoyuan Technology Development Co., Ltd., Anhui Province, China) in both groups, including ARP and MSP.

Anal function: Rectal sensory function was measured using an anorectal pressure detector and matching balloon. The patient was placed in the left lateral position, and a catheter was placed in the ampulla of the rectum. The balloon is filled with air at a constant rate of 1 mL/second. The volume of inflation when the patient first experiences defecation is the rectal sensation volume, and the total inflation volume when the patient reaches the limit of intolerance to defecation is the maximum tolerable rectal volume. The pressure difference in the rectal cavity corresponding to the maximum tolerance volume was synchronously recorded, and rectal compliance was calculated based on the formula: Rectal compliance = volume change/pressure difference. Repeat the testing of Each indicator was tested three times, and the average was taken.

Efficacy evaluation: After 3-month follow-up, the therapeutic efficacy in both groups was statistically analyzed. The criteria were: “Markedly effective” if the LARS score decreased by > 70%, and ARP and squeeze pressure increased by > 30%; “effective” if the LARS score decreased by 50%, and anal canal pressure showed improvement compared to before intervention; “ineffective” if the above criteria were not met or if the LARS score continued to increase.

Statistical analysis

Statistical analysis was performed using SPSS software (version 23.0). Categorical data are presented as n (%) and analyzed using the χ² test. Measurement data are presented as mean ± SD and analyzed using the t-test. Statistical significance was set at P < 0.05 significant.

RESULTS

Bowel movement-related indicators in both groups

There were no significant differences in bowel movement frequency or fecal incontinence frequency scores between the two groups before the intervention (P > 0.05). After intervention, the number of bowel movements in the study group was (2.64 ± 0.59) times, which was less than that in the control group (3.35 ± 0.72) times. The fecal incontinence frequency score in the study group after intervention was (2.47 ± 0.52) points, which was lower than that in the control group (4.61 ± 1.13) points, and the difference was significant (P < 0.05), as shown in Table 2.

Table 2 Comparison of defecation-related indicators between the two groups, mean ± SD.

Group	Number of bowel movements (times/day)		Frequency of fecal incontinence (points)
	Before	After	Before	After
Control group (n = 30)	5.17 ± 1.36	3.35 ± 0.72	7.12 ± 1.46	4.61 ± 1.13
Study group (n = 30)	5.28 ± 1.41	2.64 ± 0.59	7.35 ± 1.54	2.47 ± 0.52
t	0.308	4.178	0.594	9.423
P value	0.760	< 0.001	0.555	< 0.001

LARS scores in both groups

There was no significant difference in the LARS scores between the two groups before the intervention (P > 0.05). One and three months after the intervention, the LARS scores for both groups significantly decreased compared to their respective scores before the intervention. At the same follow-up time points, the intervention group exhibited significantly lower scores than the control group (P < 0.05). These findings suggest that magnetoelectric biofeedback can markedly alleviate the severity of low ARS. Furthermore, the improvement in the LARS score became more pronounced with an extended intervention duration, as shown in Table 3.

Table 3 Low Anterior Resection Syndrome scores of patients in the two groups, mean ± SD (point).

Group	Before	1 month after intervention	3 months after intervention
Control group (n = 30)	31.82 ± 3.67	24.13 ± 3.42a	15.46 ± 2.85a
Study group (n = 30)	31.95 ± 3.72	21.49 ± 3.15a	11.07 ± 2.61a
t	0.136	3.110	6.222
P value	0.892	0.003	< 0.001

^aP < 0.05 vs the pre-intervention level within the group.

MSKCC-BFI scores in both groups

Intra-group comparison: One and three months after the intervention, the MSKCC-BFI scores of both groups were significantly higher than those before the intervention (P < 0.05), and at the same time points between groups, the MSKCC-BFI scores of the study group at one month and three months after intervention were both higher than those of the control group (P < 0.05), as shown in Table 4.

Table 4 Memorial Sloan Kettering Cancer Center Bowel Function Instrument scores of patients in the two groups, mean ± SD (point).

Group	Before	1 month after intervention	3 months after intervention
Control group (n = 30)	32.17 ± 4.39	41.63 ± 5.21a	55.92 ± 6.87a
Study group (n = 30)	31.76 ± 4.68	47.18 ± 5.73a	61.67 ± 7.04a
t	0.350	3.925	3.202
P value	0.728	< 0.001	0.002

^aP < 0.05 vs the pre-intervention level within the group.

Anal pressure indicators in both groups

There were no significant differences in the ARP and MSP levels between the two groups before the intervention (P > 0.05). After the intervention, both ARP and MSP levels were significantly higher in the intervention group than in the control group (P < 0.05). See Table 5.

Table 5 Comparison of anal pressure index levels between the two groups, mean ± SD (mmHg).

Group	ARP		MSP
	Before	After	Before	After
Control group (n = 30)	37.51 ± 4.06	49.27 ± 5.13a	95.37 ± 6.43	121.56 ± 8.17a
Study group (n = 30)	37.26 ± 4.15	62.14 ± 5.08a	94.86 ± 6.75	126.89 ± 9.04a
t	0.236	9.764	0.300	2.396
P value	0.814	< 0.001	0.766	0.020

^aP < 0.05 vs the pre-intervention level within the group. ARP: Anal resting pressure; MSP: Maximum squeeze pressure.

Comparison of anorectal function between groups

There were no significant differences in any anorectal function indicators between the two groups before the intervention (P > 0.05). After the intervention, parameters including rectal first sensation volume, rectal maximum tolerated volume, and rectal compliance were significantly higher in the intervention group than in the control group (P < 0.05). See Table 6.

Table 6 Comparison of anal function between the two groups, mean ± SD.

Group	Rectal sensation of stool volume (mL)		Maximum rectal tolerance (mL)		Rectal compliance (mL/kPa)
	Before	After	Before	After	Before	After
Control group (n = 30)	61.27 ± 4.95	67.53 ± 5.81a	137.25 ± 11.61	164.17 ± 12.85a	3.56 ± 0.61	4.83 ± 0.54a
Study group (n = 30)	60.79 ± 5.13	71.39 ± 5.72a	136.84 ± 12.15	171.78 ± 12.61a	3.68 ± 0.57	5.36 ± 0.62a
t	0.369	2.593	0.134	2.315	0.787	3.531
P value	0.714	0.012	0.894	0.024	0.434	0.001

^aP < 0.05 vs the pre-intervention level within the group.

Clinical efficacy in both groups

The total efficacy rate in the study group was 96.67%, which was significantly higher than that in the control group (73.33%; P < 0.05). See Table 7.

Table 7 Comparison of therapeutic efficacy between the two groups, n (%).

Group	Excellence	Effective	Invalid	Total effective rate
Control group (n = 30)	9 (30.00)	13 (43.33)	8 (26.67)	22 (73.33)
Study group (n = 30)	15 (50.00)	14 (46.67)	1 (3.33)	29 (96.67)
t				4.706
P value				0.030

DISCUSSION

ARS following sphincter-preserving surgery for lower rectal cancer refers to a series of postoperative defecatory dysfunctions resulting from partial rectum resection, impaired rectal reservoir function, and potential effects on the anal sphincter or associated nerves[11]. Currently, nonsurgical interventions are the primary treatment for ARS after sphincter-preserving surgery for low rectal cancer, aiming to improve rectal compliance, restore pelvic floor muscle function, and regulate bowel rhythm. Surgical treatment is reserved for severe cases that are unresponsive to non-surgical interventions[12]. Previous reports have confirmed that various nonsurgical interventions, including dietary and lifestyle modifications[13], pharmacological treatment[14], pelvic floor muscle training[15], sacral nerve modulation[16], and traditional biofeedback therapy[17] are effective to some extent. However, single-modality approaches have certain limitations as basic interventions. The combined magnetic-electrical biofeedback intervention is a novel treatment regimen that integrates magnetic stimulation, electrical stimulation, and biofeedback technology. Through the synergistic effect of passive stimulation for repair and active training for reinforcement, precise treatment of the ARS can be achieved. Compared with single-modality interventions, this approach may provide broader therapeutic effects through its multimodal mechanism[18].

After intervention, the study group exhibited fewer daily bowel movements and a lower fecal incontinence frequency score than the control group (P < 0.05). Only two time points were set for defecation-related indicators: Before and three months after the intervention. The main consideration was that pelvic floor biofeedback could not reverse the entire chain of pathological changes in the short term, and that short-term values were easily affected by multiple confounding factors. In addition, one month after the anus-preserving surgery for lower rectal cancer, the patient was in the regression period of anastomotic edema and the acute compensatory disorder period of the intestinal tract. One month after the operation, there were still varying degrees of inflammatory edema in the anastomotic mucosa, and the rectal stump receptors were in a highly sensitive state. Moreover, the patient’s diet gradually transitioned from liquid to regular food postoperatively, and the intestinal flora had not yet been fully reconstructed. The frequency of defecation and incontinence fluctuated significantly in the short term. Conventional intervention in the control group primarily consisted of dietary guidance, regular bowel habit training, and Kegel exercises, providing only basic management at the behavioral level. However, such measures rely on patients’ autonomous perception and motor control and lack directness and specificity in regulating rectal and pelvic floor muscle function. In contrast, the control group received magnetic-electrical biofeedback therapy in addition to conventional interventions. Magnetic therapy directly acts on the rectal area to improve the local neuromuscular status, while biofeedback technology enables visual monitoring of rectal pressure and pelvic floor electromyographic signals. This not only guides patients in performing anal sphincter contraction and relaxation training accurately, thereby reducing compensatory movements, but also enables volume-pressure strengthening training targeting reduced rectal compliance. Reinforcing rehabilitation effects from the perspective of physiological regulation and precise training more effectively improves the core symptoms of ARS[19]. The frequencies of defecation and incontinence are the most direct external clinical manifestations in patients. The LARS is a comprehensive subjective quantitative tool that integrates multiple defecation abnormalities, such as urgency, incontinence, and difficulty in emptying. Therefore, this study further used the LARS score to quantify changes in the severity of the syndrome and found that the study group’s scores were significantly lower than those of the control group at both 1 month and 3 months post-intervention (P < 0.05). From a mechanistic perspective, although conventional intervention in the control group can alleviate ARS symptoms through diet and bowel training, it lacks the precise regulation of rectal sensation and pelvic floor muscle coordination. Symptom improvement often remains at the level of behavioral adjustment[20]. Some studies suggest that, over time, treatment effects may plateau owing to decreased patient compliance or the precision of movements[21]. Magnetic electrical biofeedback therapy in the study group continuously improved the sensitivity and compliance of local rectal neuromuscular function. In contrast, leveraging biofeedback visual training and individualized parameter adjustment helps patients gradually establish correct defecation reflexes and pelvic floor muscle control patterns. This dual effect of physiological recovery and behavioral training may contribute to progressively stronger symptom improvement over the intervention period, ultimately showing more significant advantages at 1 month and 3 months. The LARS score assesses the severity of intestinal disorders, while the MSKCC-BFI scale evaluates the impact of various defecation abnormalities on the daily quality of life of patients and is an important evaluation index for the assessment of life benefits. The MSKCC-BFI scores in the study group were significantly higher than those in the control group at both 1 month and 3 months post-intervention (P < 0.05), indicating that combined magnetic-electrical biofeedback therapy was superior to conventional intervention in improving patients’ quality of life related to bowel function. The MSKCC-BFI score directly reflects the impact of bowel dysfunction on patients’ quality of life. Although conventional interventions may improve bowel symptoms to some extent, improvements in the symptoms and quality of life are often achieved passively. The combined magnetic-electrical biofeedback therapy in the study group have more effectively alleviated core ARS symptoms by improving rectal function through magnetic stimulation and optimizing pelvic floor muscle control through biofeedback training. This also enhanced patients’ sense of control over their bowel function through visual training and effect review, reducing negative impacts such as anxiety and social avoidance caused by symptom uncertainty. This dual effect of symptom improvement and enhanced psychological and behavioral control led to a significant improvement in patients’ quality of life scores[22]. Thus, it can not only improved objective symptoms of ARS but also tangibly enhanced patients’ postoperative life experiences, which is of significant importance for the physical and psychological rehabilitation of patients after sphincter-preserving surgery for low rectal cancer.

In addition to subjective symptom assessment, anal canal pressure was evaluated as an objective indicator for evaluating the intervention effect. effect. ARP reflects the basal pressure required to maintain anal sphincter at rest to keep the anus closed, and MSP is the maximum pressure during active sphincter contraction. Together, these factors reflect the functional state of the anal sphincter[23]. Previous studies indicate have shown that, owing to surgical trauma to the rectum and pelvic floor sphincters during sphincter-preserving surgery for low rectal cancer, ARP and MSP often decrease, leading to weakened fecal control[24]. This study showed that after the intervention, both ARP and MSP levels in the intervention group were significantly higher than those in the control group (P < 0.05). The reasons for this are as follows: In the control group’s conventional intervention, although Kegel exercises train sphincter contraction, they rely on the patients’ subjective perception, making it difficult to precisely activate the target muscle groups. However, their effects on sphincter functional coordination and muscle strength recovery are limited. In the combined magnetic-electrical biofeedback therapy, magnetic therapy can directly act on the anal sphincter area in a sitting position or target the sacral nerves directly with the coil in a prone position. Magnetic stimulation may enhance muscle strength, increase muscle fiber recruitment, modulate sacral nerves, and restore damaged pelvic nerves, thereby improving local neuromuscular excitability and contractile function. Electrical biofeedback utilizes specific pulsed currents to stimulate target organs/tissues or their innervating central and peripheral nerves, thereby inducing functional changes. Combined with real-time monitoring of sphincter electromyography signals and pressure data, biofeedback guides patients in performing sphincter relaxation and contraction exercises correctly while reducing compensatory movements. This achieves dual regulation through physiological stimulation and precise training, thereby more effectively improving ARP (resting anal closure ability) and MSP (active contraction ability). These improvement in anal pressure indicators at the physiological metric level explains the mechanism by which the combined magnetic-electrical biofeedback therapy improves ARS symptoms and quality of life. Restoring anal sphincter pressure levels effectively enhances fecal control in patients with ARS and serves as an important physiological basis for improved clinical efficacy.

Anal canal pressure focuses on the ability of the anal sphincter to control defecation, whereas rectal defecation sensory capacity, maximum rectal tolerance capacity, and rectal compliance focus on rectal defecation storage and visceral sensory function. These two belong to the two key anatomical sites of the anal canal and rectum, respectively, and together, they form a complete physiological function chain of the anus and rectum. Previous studies have shown that, surgical trauma associated with sphincter-preserving surgery for low rectal cancer may alter rectal mucosal sensation and reduce rectal elasticity wall. This manifests as a decreased first sensation volume, directly contributing to frequent urges to defecate[25]. A reduced maximum tolerated volume suggests a weak fecal storage capacity in patients, whereas decreased compliance typically indicates poor rectal adaptability to internal distension. In the present study, after the intervention, the study group exhibited significantly higher rectal first sensation volume, maximum tolerated volume, and compliance compared to the control group (P < 0.05). The core reason lies in the different dimensions through which intervention protocols improve rectal function. Although the conventional intervention in the control group indirectly affected the rectal contents through dietary adjustments, it did not directly improve rectal mucosal sensation or compliance of the rectal wall. In the intervention protocol of the study group, magnetic therapy improved the sensory conduction function of the local rectal nerves, whereas biofeedback through volume-pressure training simulated the stimulation of fecal distension. This feedback may have helped patients reestablish a normal sensory threshold for rectal distension while simultaneously enhancing the elastic adaptability of the rectal wall. This direct intervention, which combined neural sensory modulation and fecal storage function training, effectively enhanced rectal urge perception, fecal storage capacity, and compliance. Overall, this approach not only improved anal sphincter pressure control but also enhanced rectal sensation and reservoir function. The synergistic action of these two aspects collectively alleviated ARS symptoms such as frequent defecation and poor control, thereby promoting the improvement of anorectal function.

The results also showed that the total efficacy rate (96.67%) was significantly higher in the study group than in the control group (73.33%), P < 0.05. From a physiological perspective, the combined magnetic-electrical biofeedback therapy enhanced both the “valve” function of the anal canal for defecation control and improved rectal first sensation volume, maximum tolerated volume, and compliance. At the symptom level, the restoration of physiological functions directly reduces the frequency of bowel movements and the incidence of fecal incontinence, achieving a progressive effect of physiological function repair, symptom alleviation, and quality of life improvement, which ultimately translates into a higher overall clinical efficacy rate. In contrast, conventional intervention primarily focused only on behavioral management and lacked precise physiological regulation of the rectal-anal function. Consequently, it was inferior to the study group in terms of symptom improvement and functional restoration, resulting in lower clinical efficacy compared to the study group. However, this study also has certain limitations. Owing to the constraints of research time and conditions, the number of case samples included in this study was relatively small, and the follow-up period was relatively short, which may have led to statistical bias in the data results. Subsequently, a multicenter control group study will attempt to expand the sample size and simultaneously extend the study duration to confirm the impact of the combined intervention plan of magnetoelectric biofeedback on the long-term prognosis of patients.

CONCLUSION

In summary, combined magnetic-electrical biofeedback demonstrated significant efficacy in patients with ARS following sphincter-preserving surgery for low rectal cancer. It improved anorectal function and rectal status while enhancing overall therapeutic outcomes. It can be considered the preferred non-surgical intervention option for patients with ARS after sphincter-preserving surgery for low rectal cancer.