Menstrual Pain

Menstrual Pain Relief with Laparoscopic Uterine Nerve Ablation (Laparoscopic Laser)®

With approximately 25% of dysmenorrheic patients reporting no improvement with non-steroidal anti-inflammatory drugs, a study was devised to evaluate the effectiveness of a laparoscopic technique for the interruption of the utero-sacral nerves. In a double-blind study of 21 patients with primary dysmenorrhea, 81% (9 of 11) reported significant relief from menstrual pain after the surgery. Performed as an outpatient procedure, laparoscopic uterine nerve ablation may alleviate dysmenorrheic complaints when other modalities have failed. Half the treated women reported continued relief of menstrual pain at 12 months. These results suggest that utero-sacral nerve interruption may prove an effective alternative treatment for this menstrual disorder.

Normal Anatomy

Dysmenorrhea, a Greek term, denotes painful menstrual flow. Approximately 50% of pubertal women have reported experiencing appreciable pain some time during menstruation.[15] With an estimated 600 million work hours lost annually to this affliction [5]--an average of two or more work days per female employee per month-dysmenorrhea has become a significant and costly illness .[14]

Dysmenorrhea is characterized by mild to severe menstrual pain occurring from a few hours prior to several days into menstruation. Affiliated symptoms have included nausea, vomiting, diarrhea and headache. Dysmenorrhea has been categorized as primary or secondary. Primary, defined as menstrual pain not associated with pelvic disease, has been noted to begin with the onset of ovulatory cycles; secondary refers to pain a definite pathologic cause of which could be identified (pelvic inflammatory disease, endometriosis, submucous fibroids, congenital defects of the mallerian system, etc .).[6]

Some researchers have suggested that dysmenorrheic patients have increased prostaglandin release in menstrual secretions and abnormal uterine contraction patterns during menstruation. [4,12] However, no simple test has yet been found to differentiate women with this syndrome from unaffected women.

An array of treatments has been suggested for the dysmenorrheic patient. Prior to 1960, the approach was often surgical interruption of the inferior hypo-gastric nerve plexus (pre-sacral neurectomy). [1,3] Since then, medical therapy with non-steroidal anti-inflammatory drugs (NSAIDS) and oral contraceptives has become the treatment of choice. However, both Henzel [6] and Dawood [10] have reported that more than 20% of dysmenorrheic patients fail to respond to NSAID therapy.

An often-ignored procedure for the treatment of dysmenorrhea has been interruption of the utero-sacral nerves. It was first described by Ruggi in 1899,[11] and European gynecologists have referred to interruption of the utero-sacral ligaments for the relief of dysmenorrhea. In 1955 Doyle studied the results of vaginally transacting the utero-sacral nerves for dysmenorrhea. He reported that over 70% of patients had relief from pain. Doyle's results were very similar to those tabulated for pre-sacral neurectomy .[ 7] Since no double-blind study of laparoscopic interruption of the utero-sacral nerves had been reported on, we undertook to examine its effectiveness using strict medical and psychological testing parameters. This study was aimed at evaluating laparoscopic uterine nerve ablation (LUNA) and its effectiveness at relieving the complaints of primary dysmenorrhea in patients for whom medical therapy with NSAIDs and oral contraceptives proved ineffective.

Materials and Methods

A relatively homogeneous group of women with severe and incapacitating dysmenorrhea was selected on the basis of rigorous criteria. Each woman documented her dysmenorrheic absence from school and/or work on a monthly calendar. Each reported no improvement with at least two NSAIDs (Motrin, Anaprox, Ponstel or Naprosyn) and an oral contraceptive taken concurrently. Indocin and butazolidin were not routinely used because of the increased risk of side effects. Oral contraceptive therapy was limited to those containing between 30 and 50 pig of estrogen. Oral contraceptive therapy was used for at least two cycles unless discontinued due to headache, depression or weight gain. Each patient reported symptoms beginning within two years of menarche and continuing to the present. After the initial interview and physical examination by the first author, 39 nulliparous women qualified for the study. The age of the patients ranged from 18 to 34 years. Subjects were excluded if they had a history of psychotherapy, major abdominal procedures or drug abuse. Women who had demonstrable pelvic pathology were also excluded.

The possibility of coexisting psychiatric illness was evaluated in an interview with the second author and with the use of the Minnesota Multiphasic Personality Inventory (MMPI). Each patient scored her pain on a five-point rating system designed by the clinical psychologist: 0 = no pain, I = mild pain requiring no medication, 2 = moderate pain responding to mild analgesia, 3 = severe pain necessitating potent pain relievers, and 4 = incapacitating pain, unresponsive to potent pain relievers, and an inability to function. All patients prospectively reported pain at levels 3 and 4, lasting for two to seven days each month.

Experimental Protocol

The project was approved by the medical research committee (internal review board) of Sinai Hospital of Detroit, an affiliate of Wayne State University College of Medicine. Informed consent was obtained from each of the 39 subjects; it included a clause that required all the patients to have diagnostic laparoscopy to determine the presence or absence of pelvic pathology. Only those patients without demonstrable pelvic pathology were to be entered into the study group. Of the study patients, half were to under LUNA. None of the patients or the clinical psychologist were to know whether a therapeutic or diagnostic procedure was performed.

The method of placement into the control LUNA group was determined by the last digit of patient's hospital medical record number, assigned on the day of surgery. Even numbers were assigned the LUNA surgical group; those with odd numbers underwent the diagnostic laparoscopic procedure only.

Of the original 39 patients, 18 were excluded on the basis of pathology. Fifteen had endometriosis, two had pelvic inflammatory disease, and one had an abnormal MMPI psychological profile. Of the remaining 21 candidates qualifying for surgery, 10 were in the control group and 11 in the LUNA group.

Surgical Technique

Routine preparation was made for diagnostic laparoscopy. With the patient intubated and under general anesthesia, the operating laparoscope was used to allow improved visualization and instrumentation of the cul-de-sac. LUNA surgery was then initiated. In the nulliparous the utero-sacral ligaments were easily identified. Care was taken to avoid lateral pelvic structures, including the ureters. The operator stretched the utero-sacral ligaments by flexing the uterus upwards toward the anterior abdominal wall. Next, using a generator (Medical Electronics Systems, model 2000) set at 5.8 W, the ligaments were coagulated at their insertion into the cervix using a 51-cm grasping forceps. Current was continued until blanching of the utero-sacrals was noted. The effect on the tissue was limited to the utero-sacral ligaments and slightly lateral. After dessication the grasping forceps were used to connect the cauterized areas in a U-like fashion along the base of the cervix. Using the mechanical operating scissors, the utero-sacral ligaments were cut through. Current was then reapplied to the depth of this incision (Figure 1-3). Cervical dilatation was not performed since it can bring temporary relief to the dysmenorrheic patient. [6,7]

Results

All 21 patients were followed for at least 12 months. None reported any complications or side effects. No statistical difference existed between the control and LUNA group based on the MMPI or psychological interview. The LUNA group reported more somatic complaints prior to surgery (Table I).

No patient in the laparoscopic group reported any relief from her dysmenorrheic complaints at 3 or 12 months after surgery. Nine of 11 patients who had LUNA reported almost complete relief from dysmenorrhea at three months. Five of these nine continued to report relief from dysmenorrhea one year after surgery.

Statistically, the Mann-Whitley U-test for paired, rank scoring showed significance below the .02 level of confidence at both the 2- and 12-month postoperative intervals (Table II). Of further importance was that women who reported surgical success also reported relief from the associated nausea, vomiting, diarrhea and headaches.

Discussion

In the 1930s, extensive anatomic dissection revealed the pathways of the sympathetic and parasympathetic fibers to the cervix and uterus. Counseller[3] noted that the sympathetic fibers from T10 to L1 were contained within the inferior hypogastric nerve, coursing along the vena cava and sacrum to enter the uterus through the utero-sacral ligaments. The parasympathetic fibers from S1 to S4 traveled within the nerve erigentes, emerging in the lateral pelvis and forming ganglia lateral to the cervix (Frankenhauser's ganglion).[2] Meigs[11] had noted that an epidural anesthetic at T10- l1 prevented the pain from endometrial curettage but not that from cervical dilatation.

The precise role of the afferent neurons in dysmenorrheic patients remains unclear. In four LUNA cases, surgical relief had been temporary, first through to be due to incomplete interruption of nerve fibers and regeneration. However, from a review of both Black (with pre-sacral neurectomy) and Doyle (with vaginal transection of the utero-sacral nerves), it seems likely that a failure rate of 30% is to be expected. Possibly the afferent fibers for these individuals are not all present in the utero-sacrals or in an identifiable pre-sacral plexus. Without performing a peri-arterial sympathectomy of the iliac and inferior mesenteric vessels, a number of these afferent fibers will be missed. These fibers are not interrupted by interruption of the central pre-sacral nerve[6] or by transection of the utero-sacral nerves.

In a number of recent patients, the CO2 laser has been incorporated to effect nerve interruption. Others using this laser technique also reported good relief from menstrual pain in more than half their surgical cases.[9]

Side effects might include uterine prolapse. No conclusion could be made based on the short time frame of this study. Although Doyle had reported relief from pain in the first stage of labor in some of his patients, the two successful LUNA patients who conceived did not report pain-free first-stage labor.

Another question unanswered by this study was the mechanism by which the reported associated systemic symptoms of nausea, vomiting, diarrhea and headache were relieved. Csapo[4] implied that the hypertentonic uterine state contributed to the increased concentration of prostaglandin F2-alpha in the menstrual fluid. He implied that this phenomenon may result in increased systemic absorption of prostaglandins. Further studies are necessary to delineate this action.

Conclusion

In recent years dysmenorrhea has emerged as a major cause of work and school absenteeism, affecting more than 18 million women in the United States. Numerous attempts to delineate the patho-physiological and social-environmental factors, have not provided complete information. The failure of NSAIDs has frustrated both patient and physician. The findings of this study support interruption of the afferent and efferent sympathetic and parasympathetic neuronal pathways of the uterus as an effective treatment for the relief of dysmenorrhea for some women.

Outpatient laparoscopic interruption of the utero-sacral nerves could offer a rational treatment for dysmenorrhea sufferers at the time of laparoscopy. A prominent advantage of this treatment is the freedom from monthly medication and often-accompanying side effects. As with older uterine nerve interruption techniques, no long-term side effects have been reported.

Further studies are necessary to better establish the underlying patho-physiology of dysmenorrhea. Complicating the issue and treatment is the social and environmental pressure that prevents women from seeking medical attention for the condition. LUNA may offer a low-risk, outpatient surgical solution to an often incapacitating and disabling disease.