Introduction

Chronic Pelvic Pain (CPP) is a distressing and intricate medical condition that has confounded healthcare professionals and significantly impaired the quality of life for a substantial portion of the adult population. This elusive condition affects up to 1 in 4 adults, making it a prevalent and burdensome health concern [1]. It is characterized by the presence of persistent pelvic pain, typically lasting for more than six months, and can result from a complex interplay of gynaecological, gastrointestinal, urological, musculoskeletal, neurological, and psychosocial factors [2]. The multifaceted and poorly understood nature of CPP presents a formidable challenge, hindering both diagnosis and treatment.

The diagnostic and therapeutic complexities associated with CPP have given rise to a pressing need for innovative approaches to alleviating the suffering experienced by affected individuals. The condition’s impact extends beyond the physical realm, taking a toll on the emotional and psychological well-being of those it afflicts. Despite its prevalence and the profound quality-of-life implications, there is a dearth of comprehensive research on effective treatment modalities for CPP. Therefore, this study is designed to address this knowledge gap by assessing the impact of a peripheral nerve block and trigger point injection protocol on Patient Reported Outcomes, aiming to offer new hope to those burdened by the persistent discomfort of CPP [3].

Furthermore, neuropathic factors, including peripheral sensitization, central sensitization, and cross-sensitization, contribute to a heightened sensitivity to pain in CPP patients [4,5]. Patients often experience hyperalgesia, where the pain that would normally be mild becomes more intense while experienced over a longer time, and allodynia, where non-painful touches cause discomfort. The intricate and not fully understood nature of CPP makes it challenging to diagnose and treat, leading to increased healthcare usage among CPP patients [1]. Treatment approaches often target various sources of pain, both through medications like anti-inflammatories, pain relievers, and other drugs affecting the nervous system, as well as non-drug therapies like physical therapy, acupuncture, lifestyle adjustments, dietary changes, cognitive-behavioral therapy, and yoga [6]. This study assesses the effectiveness of an office-based neuromuscular ultrasoundguided procedural treatment protocol targeting myofascial pain, peripheral sensitization, and central sensitization in female and male CPP patients.

Materials and Methods

Participants included in this study were 128 patients (92 women and 36 men) aged 18-76 years old diagnosed with CPP and presented to an outpatient pelvic rehabilitation practice between June 2022 and September 2023. Of the 128 patients, 73 participants were in the treatment group (those who completed the office-based ultrasound-guided peripheral nerve block and trigger point injection protocol) and 55 participants were in the control group (those who did not complete the peripheral nerve block and trigger point injection protocol). Patient demographics and clinical characteristics are depicted in Figures 1-3.

Figure 1: Age Distribution of Participants with CPP.

Figure 2: Gender Distribution of Participants with CPP.

Figure 3: Duration of Pain before PRM New Patient Visit.

To perform the research, the data was accessed on 16 January 2024 from the health portal and authors had access to information that could assist identify individual participants during or after data collection for any necessary follow-up. The protocol for this research project has been approved by a suitably constituted Ethics Committee of the institution and it conforms to the provisions of the Declaration of Helsinki. Committee of The Feinstein Institutes for Medical Research, Approval No. IRB# 17-0761. This study does not have a clinical trial number and consent forms were waived due to study design. This IRB-approved (IRB# 17‐0761) treatment was designed for patients whose symptoms persisted after participating in pelvic floor physical therapy, the first‐line treatment typically recommended for CPP. All participants underwent the following 6-week treatment protocol. For the purposes of this paper, a retrospective chart review of the protocol was performed (Figure 4).

Figure 4: Retrospective Chart Review Data Collection and Sample Selection Process.

Patients were pre-medicated with diclofenac 75 mg PO and pre-treated with a 27‐gauge needle with topical anaesthetic spray. Once weekly, participants received external ultrasound-guided trigger point injections, each delivering 1 cc of Lidocaine 1% to the pelvic musculature. A global injection was administered into the iliococcygeus, pubococcygeus, or puborectalis muscles one side at a time, targeting each muscle of the levator ani sling. This was accomplished using a flexible, 6‐inch, 27‐gauge needle inserted into the specific muscle from the subgluteal posterior approach. The procedure followed aseptic techniques under ultrasound guidance, with patients lying in a prone position. Notably, myofascial trigger points were identified on ultrasound as focal, hypoechoic zones with a diminished vibration amplitude on vibration sonoelastography, indicating the presence of a local rigid nodule [5].

Concurrently, while in the supine position, participants underwent ultrasound-guided peripheral nerve blocks of the pudendal nerve at Alcock’s canal with a subgluteal approach (Figure 5). The patient was then switched to the prone position, where a nerve block of the posterior femoral cutaneous nerve was administered 4 cm inferior to the ischial tuberosity. This occurred during each appointment, alternating between the right and left sides throughout the treatment. The initial treatment involved the placement of 2 ml of dexamethasone with 7 ml of 1% Lidocaine around each nerve on both sides. In subsequent appointments, normal saline was used for the nerve blocks instead of dexamethasone. Following the procedure, participants were able to resume their normal activities and return to work on the same day after sitting on ice for 10 minutes.

Figure 5: Ultrasound images of Alcock’s Canal and Obturator Canal.

Participant response to treatment was measured 1 year after their final treatment procedure. Differences in overall surgeries, treatments, and diagnostic procedures for patients were recorded through phone calls. The primary outcome measure is a Visual Analog Scale (VAS) score to calculate pelvic pain concentration. Patients reported their mean pain intensity from 1-10 during the previous 24 hours for the VAS score. Also, patient-reported frequency of opioid use and Emergency Room (ER visits) are utilized for a more well-rounded account of a patient’s well-being. A retrospective medical records review was conducted to analyse the above outcome measures. VAS scores are analyzed using a Wilcoxon signed-rank test, due to non-normal distribution, for paired samples. Differences in opioid use and ER Visits were tested using a McNemar test for paired proportions.

Results

Statistically significant results were achieved across several outcome variables. A VAS (Visual Analog Scale), Opioid use, and Emergency Room attendance were measured at participants’ initial appointment (New Patient Visit) and their appointment held 1 year after completion of a pelvic peripheral nerve block and trigger point injection series protocol (1 Year Follow Up).

In the treatment group, 16% of patients reported a decrease in abdominal-pelvic hernia surgeries post peripheral nerve block and trigger point injection protocol and 11% of patients reported a decrease in abdominal-pelvic hernia surgery in the control group. In the treatment group, 11% of patients reported a decrease in endometriosis surgeries post peripheral nerve block and trigger point injection protocol while 9% of patients reported a decrease in endometriosis surgery in the control group. In the treatment group, 43% of patients reported a decrease in endoscopy procedures. In the control group, 28% of patients reported a decrease in endoscopy procedures.

For the treatment group, VAS pain levels decreased by 28% from New Patient Visit with an average of 7.682 (SD 1.182; α=0.05, CI=7.175-7.684) to 1-year Follow-up average of 5.564 (SD 2.174; α=0.05, CI=5.528-5.569) (p<0.01), as shown in Figure 6. For the control group, VAS pain levels decreased by 10% from New Patient visits with an average of 7.158 (SD 1.176; α=0.05, CI=7.143-7.162) to 1-year Follow-Up average of 6.473 (SD 2.138; α=0.05, CI=6.384-6.482), also shown in Figure 6.

Figure 6: VAS Score at NPV and 1 Year Follow Up across Sample Groups.

For the treatment group, 26% of patients reported using opioids for their CPP-related pain at New Patient Visit appointment and 23% reported having gone to the Emergency Room for their CPP-related pain at New Patient Visit, shown in Figures 7 and 8. These proportions reduced to 14% and 10%, respectively, at their 1 Year Follow Up appointment, also as shown in Figures 7 and 8. This is a 12% decrease in opioid use and a 13% decrease in patients visiting the ER (both p<0.01) for the treatment group. For the control group, 15% of patients reported using opioids for their CPP-related pain at New Patient Visit appointments while 18% of patients reported using opioids for their CPP-related pain at their 1 Year Follow Up appointment. Similarly, 15% of patients reported having gone to the Emergency Room for their CPP-related pain at a New Patient Visit while 9% of patients reported having gone to the Emergency Room for their CPP-related pain at their 1 Year Follow Up appointment. This is a 3% increase in opioid use and a 6% decrease in patients visiting the ER for the control group. The treatment group also demonstrated remarkable reductions in surgeries (p<0.01) as seen in Figures 9 and 10, medical treatments (p<0.01) as seen in Figures 11 and 12, and diagnostic procedures (p<0.01) as seen in Figures 13 and 14, in comparison to the control group.

Figure 7: Opioid Usage Score at NPV and 1 Year Follow Up across Sample Groups.

Figure 8: ER Visits at NPV and 1 Year Follow Up across Sample Groups.

Figure 9: Total Lifetime Surgeries across Sample Groups.

Figure 10: Total Surgeries from June 2022 to September 2022 across Sample Groups.

Figure 11: Total Lifetime Treatments across Sample Groups.

Figure 12: Total Number of Treatments from June 2022 to September 2022 across Sample Groups.

Figure 13: Total Lifetime Diagnostic Procedures across Sample Groups.

Figure 14: Total Diagnostic Procedures from June 2022 to September 2022 across Sample Groups.

Discussion

The primary aim of this research was to assess the effects of the office-based pelvic peripheral nerve block and trigger point injection protocol on a broad spectrum of outcome parameters, encompassing pain, functionality, work productivity, quality of life, mental health, sexual health, and healthcare system utilization. It is worth noting that the average duration of pain experienced by the 128 participants in this study was 10.5 years, underscoring the chronic and debilitating nature of CPP. Patients in the treatment group, who had undergone the peripheral nerve block and trigger point injection protocol, experienced a reduction in the number of surgeries, medical treatments, and diagnostic procedures when compared to patients in the control group.