Sacral nerve stimulation

The current concept of recruiting residual function of an inadequate pelvic organ by electrostimulation involves stimulation of the sacral spinal nerves at the level of the sacral canal. The rationale for applying SNS to fecal incontinence was based on clinical observations of its effect on bowel habits and anorectal continence function in urologic patients (increased anorectal angulation and anal canal closure pressure) and on anatomic considerations: dissection demonstrated a dual peripheral nerve supply of the striated pelvic floor muscles that govern these functions. Because the sacral spinal nerve site is the most distal common location of this dual nerve supply, stimulating here can elicit both functions. Since the first application of SNS in fecal incontinence in 1994, this technique has been improved, the patient selection process modified, and the spectrum of indications expanded. At present SNS has been applied in more than 1300 patients with fecal incontinence limited.

Innovations in fecal incontinence: sacral nerve stimulation

OBJECTIVE

The aim of this study was to present an overview of sacral nerve stimulation in the treatment of fecal incontinence. We describe the evolution in technique, patient selection, and indications, and review results and complications.

METHODS

All articles on sacral nerve stimulation for fecal incontinence that were recovered on MEDLINE search were reviewed. With multiple articles from an institution, the most recent reports with the longest follow-up and largest cohort of patients were selected, unless information from earlier reports was relevant.

RESULTS

The technique of sacral stimulation is well established, carries little risk, and continues to be refined (e.g., a less invasive approach has been proposed). Patient selection is based on a two-stage diagnostic test stimulation (acute and subchronic), for which the predictive value is high. On this basis, permanent sacral nerve stimulation has proved effective in both single-center and multicenter trials in patients with a functional deficit but limited morphologic lesions or no morphologic lesions. The clinical benefit derives from multiple symptomatic improvements contributing to better bowel control and from substantially improved quality of life. The underlying mechanism of action remains undefined, but both somatic and autonomic function appears affected.

CONCLUSION

Sacral nerve stimulation offers a safe treatment mode in a patient population in whom conservative treatment has failed and traditional surgical approaches would have limited success. The high predictive value of the diagnostic approach offers a unique therapeutic advantage.

Functional outcome after intersphincteric resection of the rectum with coloanal anastomosis in low rectal cancer

OBJECTIVES

Anterior rectal resection with partial removal of the internal sphincter is an option for low rectal cancer. The objective of this study was to evaluate the functional outcome after this intersphincteric rectal resection.

METHODS

Anal continence was evaluated by anorectal manometry and a standardized questionnaire (Wexner Score) in 33 patients 28+/-15 weeks and 100+/-45 weeks, respectively, after intersphincteric resection. Nineteen of the 33 patients were reconstructed with a straight anastomosis; 12 received a colonic J-pouch.

RESULTS

Post-operatively, 25.8% of the patients were incontinent to solid stool and 54.8% were incontinent to liquid stool at least once a week. Mean and maximum resting tone (24+/-10 and 40+/-13 mmHg), maximum tolerable volume (77+/-28 ml) and rectal compliance (1.4+/-1.2 ml/mmHg) were reduced in anorectal manometry. Squeeze pressures remained unchanged. Only the maximum tolerable volume correlated significantly with the continence score (r=-0.45, p<0.05). The Wexner score and maximum tolerable volume were significantly better after colonic J-pouch reconstruction than after straight anastomosis (9.9+/-4.5 vs 13.4+/-4.0, p<0.05, 65+/-20 ml vs 100+/-27 ml, p<0.01).

CONCLUSION

Intersphincteric resection of the rectum leads to impaired post-operative continence. The functional outcome is improved with a colonic J-pouch.

Anorectal function after low anterior resection

Most patients with rectal carcinoma can now be treated with sphincter-sparing procedures. The quality of life after sphincter-sparing procedures is better than after abdominoperineal excision. However, morphology and physiology of the neorectum/ sphincter complex are challenged and enthusians towards restorative surgery in rectal cancer was tempered by concerns over functional deficits: after low anterior resection a substantial portion of patients experience impaired anorectal function, in particular fecal leakage and urgency of defecation and report disturbed sexual function. The aim of our work was to investigate functional outcome and anorectal physiologic function as measured by manometry after the three most commonly used reconstructions of intestinal continuity: anterior rectal resection, low anterior rectal, and intersphincteric rectal resection.

Rectal resection with low anastomosis: functional outcome

OBJECTIVE

Function after anterior, low anterior and intersphincteric resection for rectal cancer was studied.

METHOD

Of 139 patients 122 responded to a standardized questionnaire (Cleveland Clinic Continence Score) 108 +/- 46 weeks postoperatively and 70 underwent anorectal manometry at 26 +/- 15 weeks.

RESULTS

The postoperative continence score was dependent on the procedure (anterior resection 4.1 +/- 4.6, low anterior resection 6.9 +/- 5.6, intersphincteric resection 11.5 +/- 5.2; P < 0.0001). It was poorer after radiochemotherapy (9.0 vs. 5.7; P = 0.030), but after colonic pouch reconstruction there was no significant difference between low anterior resection (5.6 vs. 7.3) and intersphincteric resection (10.0 vs. 12.5). Mean and maximal resting pressures were significantly reduced after intersphincteric resection (24 +/- 9 and 40 +/- 13 mmHg, respectively, P < 0.001) and further reduced by radiochemotherapy. Squeeze pressure was unaffected by the operative procedures and radiochemotherapy. Maximum tolerable volume and rectal compliance were reduced, after both low anterior and intersphincteric resection. Statistical correlation between continence score and maximal resting pressure (P = 0.014), mean resting pressure (P = 0.002), urge volume (P = 0.037), and neorectal compliance (P = 0.0018) reached significance. Satisfaction with the functional outcome was expressed by 71% of patients.

CONCLUSION

After rectal resection the degree of impaired continence depended on the operative procedure and the form of reestablishment of intestinal continuity. Radiochemotherapy affected the outcome adversely. Despite reduced function, overall patient satisfaction was high.

[Sacral nerve stimulation in the treatment of faecal incontinence]

BACKGROUND

Sacral nerve stimulation is a recent development in the treatment of faecal incontinence. This paper reports the experiences of a single center on the use of this technique since its first application.

PATIENTS AND METHOD

Based on the functional results of a temporary test stimulation phase, 16 patients underwent operative implantation of a permanent neurostimulation device. Due to a functional deficit of the morphologically intact anal sphincter, all patients suffered from incontinence for liquid and solid stool. The aetiology varied among the patients. The median duration of symptoms was 8.5 years (2-30). Clinical function was evaluated by standardized questionnaires, the Cleveland Clinic incontinence score and the disease specific quality of life instrument (FIQL-ASCRS) before and during stimulation. Anorectal physiology was tested by anorectal manometry.

RESULTS

Functional improvement was achieved in 94% of the patients. At a median follow-up of 32.5 months (3-99) treatment was successful in 81%. The percentage of incontinent bowel movements decreased from a median of 40% (5-100) before stimulation to 0% (0-20) with stimulation ( P=0.001). The Cleveland Clinic incontinence score improved from a median of 17 (11-20) to 5 (0-15) ( P=0.003). The quality of life index was improved in all categories.Mean squeeze pressure was increased form a median of 44 to 75 mmHg with stimulation ( P=0.003) and maximal squeeze pressure from a median of 69 to 97 mmHg (P=0.009). Resting pressure, perception, urge threshold and maximum tolerable volume were not significantly changed.

CONCLUSION

Sacral nerve stimulation is an effective treatment for faecal incontinence. Morbidity is low. Sacral nerve stimulation is indicated, if conservative treatment fails and more conventional surgical approaches are of limited success.

Chronic sacral spinal nerve stimulation for fecal incontinence: long-term results with foramen and cuff electrodes

PURPOSE

Sacral spinal nerve stimulation is a new therapeutic approach for patients with severe fecal incontinence owing to functional deficits of the external anal sphincter. It aims to use the morphologically intact anatomy to recruit residual function. This study evaluates the long-term results of the first patients treated with this novel approach applying two techniques of sacral spinal nerve stimulator implantation.

METHODS

Six patients underwent either of two techniques for electrode placement: one "closed" (electrodes placed through the sacral foramen) and one "open" (cuff electrodes placed after sacral laminectomy). Follow-up evaluation of their continence status ranged from 5 to 66 months.

RESULTS

Incontinence improved in all patients. The percentage of incontinent bowel movements decreased during chronic stimulation from a mean of 40.2 percent to 2.8 percent, and the Wexner score decreased from a mean of 17 to 2. The function of the striated anal sphincter improved during chronic stimulation: maximum squeeze pressure increased from a mean of 48.5 mmHg to 92.7 mmHg, and median squeeze pressure increased from a mean of 37.3 mmHg to 72.5 mmHg. No complications were encountered perioperatively or postoperatively. Two devices had to be removed because of intractable pain, in one patient at the site of the electrode after five months and in the other at the site of the impulse generator after 45 months.

CONCLUSION

Long-term sacral spinal nerve stimulation persistently improves continence and increases striated anal sphincter function in patients with fecal incontinence owing to functional deficits, but in whom the striated anal sphincter is morphologically intact. Two different operative approaches can be applied effectively.

[Can continence function after rectal resection be prognostically estimated?]

AIM

To determine clinical and physiologic parameters enabling the prognosis of continence after protective ileostomy closure secondary to rectal resection for rectal cancer.

METHODS

Patients who had undergone rectal resection (n = 65, of whom 24 had had radiochemotherapy) were evaluated by clinical examination, anorectal manometry and orthograde contrast enema before ileostomy closure. Continence was evaluated by clinical findings 91 +/- 52 weeks after stoma closure with the help of standardized questionnaires and classified according to the Wexner continence score. The relationship between findings before stoma closure and continence score was calculated with Pearson's correlation coefficient.

RESULTS

Correlations were found to be significant between the continence score and the level of anastomosis (r = -0.58, p < 0.001), median resting pressure (r = -0.52, p < 0.001), rectal compliance (r = -0.43, p < 0.001). Additionally, radiochemotherapy impairs continence (p = 0.0001). Correlations were not significant between continence and functional sphincter length, squeeze pressure, threshold for perception, urge and maximal tolerable volume, and continence for semiliquid contrast medium.

CONCLUSION

Incontinence after rectum resection is multifactorial: the level of anastomosis, resting pressure, rectal compliance and radiochemotherapy all play a dominant role. Based on these findings, the continence score can be calculated before closure of a diverting ileostomy by applying multivariate analysis with the help of the following formula: Continence score = 18.23 - 0.94 x level of anastomosis - 0.18 x resting pressure + 3.72 x radiochemotherapy.

[Treatment of insufficiency of the anal sphincter by sacral spinal nerve stimulation with implantable neurostimulators]

The feasibility of permanent electrostimulation of the sacral spinal nerves was studied in patients with fecal incontinence and no detectable morphological lesions and thus not amenable to conventional surgical management. Applying acute percutaneous stimulation with needle electrodes, the most relevant sacral spinal nerve for striated sphincter muscle function was identified (sacral spinal nerve S3 or S4). The therapeutic potential of stimulation was tested by subchronic stimulation with temporary wire electrodes and, if effective, permanent electrodes were implanted in four patients. Long-term sacral spinal nerve stimulation persistently improved anal continence and increased the function of the striated muscular anal sphincter.

Low-field magnetic resonance imaging of the pelvis in patients with anal dynamic graciloplasty: initial experience

The aim of this study was to determine whether low-field magnetic resonance (MR) imaging can safely and accurately depict inflammatory changes in patients with anal dynamic graciloplasty, in whom high-field MR imaging is contraindicated and ultrasonography and computed tomography are inadequate. A 0.2-T field-strength MR examination was performed in six patients with anal dynamic graciloplasty malfunction in whom reoperation was contemplated. The following sequences were applied: T2-weighted turbo spinecho with fat saturation, T1-weighted conventional spin-echo, and contrast-enhanced T1-weighted conventional spin-echo with fat saturation. Results indicated that none of the patients experienced relevant discomfort, pacemaker malfunction, or electrode dislocation with low-field MR imaging. Inflammatory pelvic changes were visualized in four patients and atrophy of the transposed gracilis muscle in another. Surgery was thus avoided in the four, who underwent conservative treatment for their pelvic inflammation. It was concluded that these preliminary results demonstrate the feasibility of MR imaging with a low field strength in patients with anal dynamic graciloplasty. In such patients, in whom diagnostic imaging had been problematic, the potential for safe and accurate visualization will be a boon to treatment planning.

Possibilities of extensive surgery

Advances in surgical technique and knowledge of tumor biology have led to an algorithm of surgical treatment of rectal cancer, which offers three options: transanal local excision, sphincter-saving procedures (low anterior resection and, recently, intersphincteric abdomino-peranal resection), and abdomino-perineal resection of the rectum. The choice of operative procedure aiming to fulfill both oncological and functional criteria is determined by the anatomic location of the tumor, the tumor differentiation, the depth of tumor invasion, and preoperative anal sphincter function. Following the algorithm of treatment, a clear decrease can be noted during recent years in the number of abdomino-perineal resections and a shift towards sphincter-sparing procedures, without jeopardizing long-term survival. Although anal sphincter morphology can usually be maintained, preserving the anal sphincter does not necessarily mean preserving the sphincter function. The functional outcome must be judged by objective, measurable parameters and by the impact of operative sequelae on quality of life and its acceptance by the patient. Future work must focus on further improving long-term survival and functional outcome. Technical advances (Goligher et al. 1979; Heald 1980) and an improved understanding of tumor biology, especially metastatic behavior, have resulted in varied strategies for the operative treatment of rectal cancer. The common aims of these techniques are local control, avoidance of local recurrence, and--while still satisfying oncologic requirements--preservation of the anal sphincter. Until the 1970s, abdominoperineal excision was the treatment of choice. Subsequently, a shift toward anterior and low anterior resection of the rectum took place. Initially these procedures were limited to the treatment of tumors in the upper and mid rectum (Table 1) (Gall and Hermanek 1992), but the indication for anterior resection was later extended to tumors of the lower rectum (Table 2) (Hohenberger and Hermanek 1992).

Continence after colorectal reconstruction following resection: impact of level of anastomosis

In 48 patients who had undergone anterior resection for rectal cancer with straight colorectal reconstruction, clinical and manometric results were correlated with the level of anastomosis. Patients were divided into four groups by anastomotic level: < or = 3, 4-6, 7-9, and > or = 10 cm. Functional outcome with regard to frequency of bowel movements, minor leakage, fecal incontinence. ability to defer stool and to differentiate consistency showed increasing impairment the lower the anastomotic level. Frequency, leakage owing to the inability to defer stool, incontinence for solid stool, inability to discriminate flatus from stool, and incomplete emptying were significantly different (P < 0.05) between the patients with an anastomotic level between 3-6 cm and between 7-9 cm. Manometric data revealed no trend or significant differences among the groups with regard to anal resting pressure and maximal and median squeeze pressure. Rectoanal inhibitory reflex was abolished in 60% of the patients. Clear changes, with a trend toward reduced function with lower anastomotic levels, were seen in the volume that produced a feeling of urgency, maximal tolerable volume, and neorectal compliance (between anastomotic levels 7-9 and > or = 10 cm the differences were significant; P < 0.05). Analysis by length of residual rectum (< 1.5, 1.5-4.0, 4.1-6.5, > 6.5 cm) demonstrated similar findings, suggesting that impaired function after rectal resection is due to reduced function of the neorectum. Thus, as much residual rectum as possible should be preserve without risking cure. If the level of the anastomosis is expected to be below 6 cm, or if the residual rectum is less than 4 cm, the construction of a colon pouch to increase neorectal capacity should be considered.

Electrical stimulation of sacral spinal nerves for treatment of faecal incontinence

Functional deficits of the striated anal sphincteric muscles without any apparent gross defect often result in a lack of ability to postpone defaecation by intention or in faecal incontinence in response to increased intra-abdominal or intra-rectal pressure. We applied electrostimulation to the sacral spinal nerves to increase function of the striated muscles of the anal sphincter. Of three patients followed for 6 months, two gained full continence and one improved from gross incontinence to minor soiling. Closure pressure of the anal canal increased in all. Preliminary data indicate that anal closure pressure increases with the duration of stimulation. Continuous stimulation of sacral spinal nerves can help some patients with faecal incontinence. It may be possible to promote continence with intermittent stimulation.

[Permanent electrostimulation of sacral spinal nerves with an implantable neurostimulator in treatment of fecal incontinence]

Functional deficits of the striated muscular anal sphincter frequently result in faecal incontinence. The therapeutic options for patients without a defined muscular defect are limited. Our patient without defined lesion, but with a clinically relevant reduction of the voluntary force of the anal sphincter resulting in daily loss of stool, underwent an electrostimulation procedure of the sacral spinal nerves. The procedure was divided in three steps: acute percutaneous testing, temporary percutaneous nerve evaluation and permanent electrostimulation phase with an implantable neurostimulation device. In all three phases electrostimulation of the third sacral spinal nerve resulted in a positive clinical effect and an increase of the anal canal closure pressure. By application of permanent electrostimulation of the third sacral spinal nerve the patient became completely continent.

[Direct electrostimulation of sacral spinal nerves within the scope of the diagnosis of anorectal function]

A technique is demonstrated to evaluate the functional relevance of the sacral spinal nerves regarding anal sphincter function. Sacral spinal nerves S2, S3, S4 can be reached selectively for electrical stimulation by a dorsal approach through the sacral foramina. Electrical stimulation of S3 and S4 results in visible contraction of the different striated muscular anal sphincter components and in an increase of anal canal closure pressure. These effects differ among individuals. Thus, the functional relevance of each single sacral spinal nerve on the striated muscular anal sphincter can be tested specifically.