J Manipulative Physiol Ther 2008 (Mar); 31 (3): 237–246 ~ FULL TEXT
Denise A. Holtzman, DC, Kristina L. Petrocco-Napuli, DC, MS, Jeanmarie R. Burke, PhD
Clinical Sciences Department,
New York Chiropractic College,
Seneca Falls, NY 13148, USA.
OBJECTIVE: The objective of this prospective case series was to collect preliminary data as to the effectiveness of a specific chiropractic technique, drop table method, in the treatment of primary dysmenorrhea.
METHODS: Over a 4-week period, 16 females were screened for symptoms of primary dysmenorrhea and motion restrictions of the lumbosacral spine. Thirteen subjects were enrolled into the study. Bilateral and unilateral lumbosacral flexion and extension restrictions were treated using drop table manipulations 3 times during each of the 2 consecutive menstrual cycles. Before entering the study and at the end of each menstrual cycle, the subjects self-reported ratings of menstrual pain (abdominal, pelvic, and low back pain) and associated symptoms of primary dysmenorrhea using Numeric Pain Scale. Numeric Pain Scale ratings for menstrual pain were the primary outcome measures.
RESULTS: The median age was 26 years, and the median self-reported duration of the symptoms was 12 years. At baseline, all subjects reported pain severity scores of 5 or higher for at least 2 of 3 anatomical sites: lower or general abdominal pain and/or lower back pain. Using the 95% confidence interval (CI) as an estimate, clinically meaningful changes (<5) in general abdominal pain and lower back pain were evident for most patients during the treatment phase, whereas for lower abdominal pain, the improvements were subject and cycle dependent.
CONCLUSIONS: Menstrual pain associated with primary dysmenorrhea may be alleviated with treatment of motion segment restrictions of the lumbosacral spine with drop table technique.
From the FULL TEXT Article
Although the limited evidence from 4 trials of high-velocity low-amplitude manipulation and one of Toftness manipulation did not support the clinical efficacy of spinal manipulation for menstrual pain,  the objective of this prospective case series was to collect preliminary data as to the effectiveness of a specific chiropractic technique, drop table methods in the treatment of primary dysmenorrhea. The interpretation of our preliminary data indicates that menstrual pain associated with primary dysmenorrhea was alleviated by treating motion segment restrictions of the lumbosacral spine with a drop table technique. Secondary outcomes were not as bothersome to our patients, and the lack of a clinical treatment effect of the drop table technique on these symptoms was an expected finding.
As described in the introduction, neuromechanical mechanisms underlying the potential effectiveness of spinal manipulation for dysmenorrhea may involve decreasing tension on the broad ligament of the uterus and sacral nerve roots. Based upon neurologic connection between uterine function and the sacral nerve roots, a resultant sympathetic response to spinal manipulation may inhibit uterine contraction and increase blood flow to the pelvic region. In support of potential neuromechanical mechanisms, our subjects presented with motion segment restrictions of the lumbosacral spine. These data were consistent with a previous study documenting a moderate correlation (r = 0.43) between SI joint dysfunction and the symptoms of dysmenorrhea.  Specifically, motion palpation procedures were used to identify SI joint dysfunction and then were correlated with subjective symptom ratings on the MDQ. 
Restrictions of the lumbosacral spine persisted in all our subjects at each treatment visit. As such, the self-reported decrease in menstrual pain with the drop table technique may suggest an acute effect of spinal manipulation on pelvic nerve pathways associated with uterine dysfunction and primary dysmenorrhea. The resolution of neuromechanical dysfunction of the lumbosacral spinal and the associated uterine dysfunction with spinal manipulation may require a longer duration intervention to restore normal joint function. In addition, the strength of relationship between neuromechanical dysfunction of the lumbosacral spinal and symptoms of primary dysmenorrhea need to be more conclusively established. The reliability and validity of motion palpation procedures, although routine in clinical practice, also need to be substantiated for the purposes of evidence-based investigations.
Similar to research addressing roles of calcium carbonate supplements and an anti-inflammatory diet, another potential underlying mechanism for spinal manipulative procedures may be a time-dependent attenuation of proinflammatory cytokine secretion.  Thus, it may be hypothesized that spinal manipulations may alleviate pelvic pain through anti-inflammatory mechanisms. However, previous research on the effect of spinal manipulation on pain and prostaglandin levels in women with primary dysmenorrhea does not support a potential anti-inflammatory mechanism. [11, 12]
The limitations of the study were a small sample size, no control group, a study population of chiropractic students, and the durations of the treatment intervention and baseline monitoring of symptoms. During the treatment phase of 2 months, the subjects continued to present with lumbosacral restrictions. The clinical improvements in the severity of menstrual pain may be due to a palliative treatment effect. Thus, patients would need to seek chiropractic care every month to prevent/alleviate menstrual pain as opposed to the more beneficial effect of restoring motion segment function to alleviate the chronically occurring health condition of primary dysmenorrhea. Although the median duration of symptoms of primary dysmenorrhea was 12 years for our subjects with a consistent presentation of symptoms during each menstrual cycle, the baseline assessment only rated the severity of the symptoms of their previous menstrual cycle before enrollment in the treatment phase. Normal variations in the severity of symptoms of primary dysmenorrhea of our subjects are unknown and may only be assumed to be moderate to severe during every menstrual cycle when the subjects did not receive chiropractic care or use other alternative or allopathic interventions.
Despite these limitations, the evidence from this prospective case series report provides insights on designing feasibility trials to evaluate this specific drop table technique for primary dysmenorrhea. Our future research will involve recruiting community dwelling female patients with primary dysmenorrhea and randomizing them into a treatment group (n = 30) and a sham control group (n = 30). The treatment phase will be 6 months. It is hypothesized, with this longer treatment phase, that some subjects in the treatment group may begin to present with no restrictions of the lumbosacral spine at months 5 and 6, and the severity of menstrual pain will decrease. This would begin to determine the role of chiropractic treatment as a palliative alternative therapy for menstrual pain or as effective intervention for treating the chronic symptoms associated with primary dysmenorrhea. The dose-response for the former treatment effect is as described in this report and would then need to be confirmed with a large-scale randomized controlled trial, whereas dose-response for the latter treatment effect would require further feasibility trials before pursuing a large-scale randomized controlled trial.
This prospective case series suggests the possibility that menstrual pain associated with primary dysmenorrhea may be alleviated by treating motion segment restrictions of the lumbosacral spine with a drop table technique. The research team needs to conduct a well-designed feasibility trial to further evaluate the effectiveness of this specific spinal manipulative technique for primary dysmenorrhea.
Chiropractic treatment of the lumbosacral region of the spine may have neurologic as well as musculoskeletal implications regarding primary dysmenorrhea.
Drop table manipulations alleviated menstrual pain due to primary dysmenorrhea in the participants of this study.