High-resolution ultrasound of the posterior femoral cutaneous nerve: visualization and initial experience with patients

The Gluteus Deep Investing Fascia Compartment Block: A Novel Technique for Posterior Femoral Cutaneous Nerve Block

Purpose

The posterior femoral cutaneous nerve (PFCN) block is used in regional anesthesia for lower extremity surgery. This study introduces a new ultrasound-guided technique called the "Gluteus-Deep Investing Fascia compartment Block (GDIF block)" for blocking the PFCN. This approach involves injecting local anesthetic into the potential space between the gluteus maximus muscle and the deep investing fascia, named the 'Gluteus Deep Investing Fascia Compartment'. The study discusses the anatomical and sonographic features crucial for identifying this compartment and explores the potential benefits of this approach for achieving effective PFCN block. Additionally, it examines the clinical application of the GDIF block for PFCN block as part of the Complete Lower Extremity Fascia Tri-compartment Block technique, named "CLEFT Block." This technique combines the suprainguinal fascia iliaca block with GDIF compartment block for PFCN and a sciatic nerve block as exclusive anesthesia technique.

Patients and Methods

Nine patients with weapon-related lower limb injuries underwent surgery at district hospitals supported by the International Committee of the Red Cross. Between October and December 2023, seventeen above-knee procedures were performed for the nine patients using the GDIF block as part of a CLEFT block technique. Anesthesia was performed with a CLEFT block technique using a volume ratio of 1:1 of 1% lidocaine and 0.5% levobupivacaine.

Results

The GDIF block technique for PFCN blockade was performed successfully in all patients without complications, achieving complete PFCN blockade. The CLEFT block technique proved effective as the sole anesthetic technique for seventeen above-knee procedures. All surgeries were completed successfully without additional pain medication or conversion to general anesthesia.

Conclusion

The GDIF block appears to be a promising technique for anesthetic management, alone or as part of the CLEFT block. Further research with a larger patient population is necessary to validate these findings.

Beyond the obvious: A case presentation on the misdiagnosis of posterior femoral cutaneous nerve entrapment as semitendinosus muscle tear

To underscore the importance of evaluating the entrapment of the posterior femoral cutaneous nerve (PFCN) in patients exhibiting symptoms in the posterior thigh region. A 42-year-old male dentist, initially diagnosed with a semitendinosus muscle tear and persistent pain and tingling in the posterior thigh, sought treatment at our outpatient clinic. Despite unsuccessful physiotherapy, a comprehensive evaluation revealed an unusual entrapment of the PFCN between the sacrotuberous ligament and the semitendinosus muscle stump. The patient was subjected to a series of specialized therapeutic interventions, including soft tissue release, kinesiology taping, and lifestyle modifications. The patient's symptoms, including pain and tingling, were completely resolved, enabling him to sit on a stool for extended periods without discomfort. This case presentation emphasizes the need for physical therapists to consider the possibility of PFCN entrapment in patients experiencing pain and tingling in the posterior thigh. These symptoms can be easily mistaken for conditions such as sciatica or a hamstring muscle tear.

Posterior femoral cutaneous nerve impingement post marathon: A case report

INTRODUCTION

Posterior femoral cutaneous nerve (PFCN) neuropathy is an uncommon, potentially under-recognized cause of low back, buttock, perineal, and posterior and lateral thigh pain and numbness. Most PFCN injuries are caused by intramuscular injections; however, this is the first reported case of a PFCN injury of hamstring pathology due to tendonitis caused by long-distance running.

CASE REPORT

A middle-aged man presented with right lower buttock pain, which started 2 weeks after running a marathon. The pain was located medial and superior to the ischia tuberosity and extended distally to the right scrotum with no testicular pain. The pain progressed such that he was unable to sit down for over a year. An initial MRI showed right hamstring tendonitis. Consults with sports medicine and hip orthopedics provided no clear diagnosis. He failed to improve with NSAIDs, physical therapy, massage, PRP injection, two Ganglion of Impar Nerve blocks, and trial of Pregabalin. The diagnosis was confirmed with temporary relief following a PFCN block. He was then advised to have the nerve resected because of the failure of nonsurgical treatment.

DISCUSSION

After excluding the more common etiologies of buttock pain and sitting intolerance, practitioners should consider the rarer condition of the impingement of the PFCN in runners.

Pain Specialist Management of Sexual Pain-II: Interventional

INTRODUCTION

Treatment of female sexual pain often requires the use of diverse modalities crossing multiple medical disciplines. Interventional procedures are important in the diagnosis and treatment of female sexual pain. Pain specialists and other medical specialties can provide these capabilities.

OBJECTIVES

To provide a current summary of the procedures used in the diagnosis and treatment of female sexual pain.

METHODS

The internet, PubMed, and the Cochrane Library were searched for relevant articles on female sexual pain within the clinical purview and scope of the practice of pain management.

RESULTS

A thorough review of the literature was conducted to include basic science studies, clinical trials, systematic reviews, consensus statements, and case reports. An effort was made to also include a sampling of information on real-world patient self-directed therapies. Descriptions of interventional procedures for the diagnosis and treatment of sexual pain were made and clinical studies reviewed. The evidence for the use of various interventional treatment strategies for sexual pain was assessed.

CONCLUSIONS

The process of care for female sexual pain employs an interdisciplinary biopsychosocial model that includes a role for interventional procedures commonly performed by pain management specialists. These specialists are a resource of knowledge, skills, and abilities that can be used to improve the care of women with chronic sexual pain.

Posterior femoral cutaneous nerve sensory conduction study in a sample of apparently healthy Egyptian volunteers

Background

Posterior femoral cutaneous nerve (posterior cutaneous nerve of the thigh) is a sensory nerve arises from the sacral plexus. Its terminal part supplies the skin of the posterior surface of the thigh and popliteal fossa, and it extends for a variable length below the popliteal fossa till the mid-calf region. The aim was to assess the posterior femoral cutaneous nerve antidromic sensory conduction technique and estimate its different sensory nerve action potential parameters’ reference values in a sample of apparently healthy Egyptian participants. One hundred and twenty lower limbs of 60 apparently healthy Egyptian volunteers were included. Clinical evaluation and sensory conduction study for the posterior femoral cutaneous nerve were done.

Results

Posterior femoral cutaneous nerve sensory nerve action potential was elicited in 98 lower limbs (81.6%) of 52 individuals (86.7%). The obtained results of different parameters of posterior femoral cutaneous nerve sensory nerve action potential were as the following: onset latency (2.04 ± 0.21 ms), peak latency (2.86 ± 0.25 ms), conduction velocity (59.45 ± 6.36 m/s) and amplitude (6.16 ± 2.29 μV). No significant differences between the two genders were found regarding different parameters of posterior femoral cutaneous nerve sensory nerve action potential except for amplitude which was significantly larger among male participants (P = 0.030). No significant differences between the right and left lower limbs were found regarding different parameters of sensory nerve action potential. There was a statistical significant negative correlation between age and posterior femoral cutaneous nerve conduction velocity (P = 0.008). There was a statistical significant positive correlation between height and peak latency (P ≤ 0.0001), as well as, a statistical significant negative correlation between height and conduction velocity (P ≤ 0.0001). There was a statistical significant negative correlation between body mass index and posterior femoral cutaneous nerve peak latency (P = 0.008).

Conclusions

The research provides a reliable electrophysiological antidromic sensory conduction study for the posterior femoral cutaneous nerve and normal cut-off reference values for posterior femoral cutaneous nerve sensory nerve action potential parameters. This is essential for the evaluation of suspected posterior femoral cutaneous nerve lesions.

Ultrasound of Small Nerves

Nerve ultrasound has become an integral part of the diagnostic workup of peripheral neuropathies. Especially in the examination of small nerves, ultrasound provides superior image quality by using high frequency transducers. For a selection of small nerves, this article summarizes the local anatomy and common pathologies and offers simple instructions for determining their location with ultrasound including some cases with pathologies. This selection of nerves comprises the great auricular nerve, the supraclavicular nerves, the suprascapular nerve, the medial antebrachial cutaneous nerve, the lateral antebrachial cutaneous nerve, the palmar cutaneous branch of the median nerve, the long thoracic nerve, the intercostobrachial nerve, the posterior cutaneous nerve, the infrapatellar branch of the saphenous nerve, the medial calcaneal nerve, and the deep peroneal nerve at the ankle. Following our recommendations, these nerves can be swiftly located and tracked along their course to the site of the pathology.

Unique Considerations for Complete Surgical Analgesia for Below-the-Knee Amputations

Recent cadaver studies have suggested that posterior femoral cutaneous nerve (PFCN) may contribute to the sensory innervation of the posterior lower leg. Whether this is clinically relevant may be revealed in patients who underwent below-the-knee amputation (BKA) with monitored anesthesia care (MAC) and peripheral nerve blocks. We performed femoral and sciatic nerve blocks for a 55-year-old male patient who underwent BKA and subsequent formalization surgeries as the main surgical analgesia while providing MAC in the operating room. In both cases, the patient could not tolerate surgical incisions in the posteromedial aspect of the lower leg, despite reporting no pain in other areas of the lower leg with surgical stimulation. There may exist a small population of patients in which PFCN makes significant contribution to the sensory innervation of the posterior lower leg. For these patients, the combination of femoral and sciatic nerve blocks may not be adequate in providing surgical analgesia for BKA and related procedures.

Ultrasound Imaging of Cutaneous Innervations of the Lower Extremity

Ultrasound (US) is commonly used to evaluate the cutaneous innervation of the lower extremity, owing to the following advantages: (1) US is a high-resolution soft tissue imaging modality; (2) it is feasible in patients who are deemed unsuitable to undergo magnetic resonance imaging; and (3) it enables dynamic and real-time imaging. The evaluation of cutaneous nerves requires accurate knowledge of the anatomy as well as technical details. We present a review of the US anatomy of the cutaneous nerves in the lower extremity in addition to a description of a few pathologic conditions.

High-Resolution Ultrasonography of the Transverse Cervical Nerve

The transverse cervical nerve (TCN) is a superficial cutaneous branch of the cervical plexus that innervates the skin of the anterolateral neck. Therefore, it is exposed to injury in anterolateral cervical surgery, which can cause neuropathic pain. To provide a method with which to relieve patients' pain, this study aimed to evaluate the possibility of visualization, diagnostic assessment and blockade of the TCN with high-resolution ultrasound (HRUS). HRUS with high-frequency probes (15-22 MHz), guided ink-marking and consecutive dissection on both sides in nine fresh cadaver necks (n = 18) was conducted. On both sides of 20 healthy volunteers (n = 40), the distances between the greater auricular nerve (GAN) and the TCN at the posterior border of the sternocleidomastoid muscle were measured. Finally, cases referred to HRUS examinations because suspected TCN lesions were assessed. The TCN was visible in all anatomic specimens and in healthy volunteers. Dissection confirmed HRUS findings in all anatomic specimens (100%). In healthy volunteers, the mean distance between the GAN and the TCN was 10.42 ± 3.20 mm. The median visibility, rated on a five-point Likert scale, was four, reflecting good diagnostic quality. There were six patients with visible abnormalities on HRUS. This study confirmed the reliable visualization of the TCN with HRUS in anatomic specimens, healthy volunteers and patients.

Cutaneous nerve fields of the anteromedial lower limb-Determination with selective ultrasound-guided nerve blockade

BACKGROUND

This study aimed to determine the peripheral cutaneous nerve fields (CNF), their variability, and potential overlap by selectively blocking the intermediate (IFCN) and medial (MFCN) femoral cutaneous nerves and the infrapatellar branch of the saphenous nerve (IPBSN) in healthy volunteers.

METHODS

In this prospective study, ultrasound-guided nerve blockades of the IFCN, MFCN, and IPBSN in 14 healthy volunteers were administered. High-frequency probes (15-22 MHz) and 1 ml of 1% lidocaine per nerve were used. The area of sensory loss was determined using a pinprick, and all fields were drawn on volunteers' skin. A three-dimensional (3D) scan of all lower limbs was obtained and the three CNF and their potential overlap were measured.

RESULTS

The mean size of innervation areas showed a high variability of peripheral CNF, with 258.58 ± 148.26 mm² (95% CI, 169-348.18 mm² ) for the IFCN, 193.26 ± 72.08 mm² (95% CI, 124.45-262.08 mm² ) for the MFCN, and 166.78 ± 121.30 mm² (95% CI, 94.1-239.46 mm² ) for the IPBSN. In 11 volunteers, we could evaluate an overlap between the IFCN and MFCN (range, 4.11-139.68 ± 42.70 mm² ), and, in 10 volunteers, between the MFCN and IPBSN (range, 11.12-224.95 ± 79.61 mm² ). In only three volunteers was an overlap area found between the IFCN and IPBSN (range, 7.46-224.95 ± 88.88 mm² ). The 3D-scans confirmed the high variability of the peripheral CNF.

CONCLUSIONS

Our study successfully determined CNF, their variability, and the overlap of the MFCN, IFCN, and IPBSN in healthy volunteers. Therefore, we encourage physicians to use selective nerve blockades to correctly determine peripheral CNF at the anteromedial lower limb.

Ultrasound Features of the Proximal Hamstring Muscle-Tendon-Bone Unit

The hamstring muscle complex is made by a group of posterior biarticular thigh muscles, originating at the ischial tuberosity, which extend the hip and flex the knee joint. Proximal hamstring injuries are frequent among athletes, commonly involving their long myotendinous junction during an eccentric contraction. In this pictorial essay, we describe the ultrasound technique to visualize the normal anatomy of the proximal hamstring muscle-tendon-bone complex and present ultrasound findings in patients with traumatic injuries and tendinopathies.

Lower extremity regional anesthesia: essentials of our current understanding

The advent of ultrasound guidance has led to a renewed interest in regional anesthesia of the lower limb. In keeping with the American Society of Regional Anesthesia and Pain Medicine's ongoing commitment to provide intensive evidence-based education, this article presents a complete update of the 2005 comprehensive review on lower extremity peripheral nerve blocks. The current review article strives to (1) summarize the pertinent anatomy of the lumbar and sacral plexuses, (2) discuss the optimal approaches and techniques for lower limb regional anesthesia, (3) present evidence to guide the selection of pharmacological agents and adjuvants, (4) describe potential complications associated with lower extremity nerve blocks, and (5) identify informational gaps pertaining to outcomes, which warrant further investigation.

Ultrasound Imaging for the Cutaneous Nerves of the Extremities and Relevant Entrapment Syndromes: From Anatomy to Clinical Implications

Cutaneous nerve entrapment plays an important role in neuropathic pain syndrome. Due to the advancement of ultrasound technology, the cutaneous nerves can be visualized by high-resolution ultrasound. As the cutaneous nerves course superficially in the subcutaneous layer, they are vulnerable to entrapment or collateral damage in traumatic insults. Scanning of the cutaneous nerves is challenging due to fewer anatomic landmarks for referencing. Therefore, the aim of the present article is to summarize the anatomy of the limb cutaneous nerves, to elaborate the scanning techniques, and also to discuss the clinical implications of pertinent entrapment syndromes of the medial brachial cutaneous nerve, intercostobrachial cutaneous nerve, medial antebrachial cutaneous nerve, lateral antebrachial cutaneous nerve, posterior antebrachial cutaneous nerve, superficial branch of the radial nerve, dorsal cutaneous branch of the ulnar nerve, palmar cutaneous branch of the median nerve, anterior femoral cutaneous nerve, posterior femoral cutaneous nerve, lateral femoral cutaneous nerve, sural nerve, and saphenous nerve.

Ultrasound-Guided Posterior Femoral Cutaneous Nerve Block: A Cadaveric Study

OBJECTIVES

To identify any anatomic barriers to local anesthetic spread between the sciatic nerve (SN) and the posterior femoral cutaneous nerve (PFCN) at the level of the infragluteal crease and to describe a potential technique for an ultrasound (US)-guided subgluteal PFCN block in a cadaveric model.

METHODS

Bilateral US-guided subgluteal injections of a colored latex solution were performed around the SN (15 mL) and PFCN (10 mL) in 4 unembalmed cadavers, for a total of 8 cadaver thighs. The specimens were dissected after latex polymerization to observe the spread of the latex solutions.

RESULTS

With US guidance, the PFCN was visualized deep to the gluteus maximus and slightly superficial or lateral to the SN at the level of the infragluteal crease. The SN and PFCN were found on dissection to be coated with their respective colored latex in all 8 thighs. The SN and PFCN were consistently separated by the deep investing muscular fascia of the thigh, with only 2 thighs showing substantial mixing of latex injectates.

CONCLUSIONS

The deep investing muscular fascia of the thigh appears to impede the spread of injectate between the SN and PFCN in a most unembalmed cadaver specimens. A US-guided subgluteal PFCN blockade may be a feasible technique to complement an SN block when complete anesthesia of the posterior thigh is required.

A brief report on a technical description of ultrasound-guided lumbar sympathetic block

The lumbar sympathetic ganglion block (LSGB) is widely used for diagnosing and treating sympathetically maintained pain disorders. The LSGB has been conventionally carried out under fluoroscopy or computed tomography guidance. However, as ultrasound technology improved, ultrasound-guided interventions have been expanding their territory to deeper structures. Ultrasound guidance provides many benefits including protecting vascular injection, shortening procedure time in some cases, and reducing the emission of radiation. In this report, we describe a successful case of a US-guided LSGB without major complications. We expect that US-guided LSGBs can be implemented and furnished in the daily outpatient clinical setting by highly trained pain physicians.