Editorial Commentary: The Optimal Nerve Block for Hip Arthroscopy Is Undetermined

The optimal nerve block to help reduce pain after hip arthroscopy is undetermined. The fascia iliaca block was en vogue but may result in weakness, neuropathy, and equivocal pain outcomes. Other options include blocks to the femoral nerve, the lumbar plexus, the quadratus lumborum, and, more recently, the pericapsular nerve group block (PENG), in which ultrasound guidance allows injection under the iliopsoas muscle to affect the accessory obturator nerve and the articular branches of the femoral nerve. PENG block should not result in weakness, but weakness has been reported after PENG block for total hip arthroplasty, and falls could be a risk and a concern. The arthroplasty literature also suggests the PENG block adds little benefit to intra-articular injection beyond the recovery room and is comparable with a fascia iliac block. Perhaps the PENG block could show benefit in select cases such as for severe postoperative pain or in patients with anticipated pain control challenges. Until an ideal block for hip arthroscopy is determined, a patient tailored approach is indicated.     

Editorial Commentary: Femoral Nerve Block: Don’t Kill the Motor Branch

Femoral nerve block is commonly used for pain control after knee surgery and helps to reduce the need for opioids in the early postoperative period. The potential disadvantage is blockage of the motor branch of the femoral nerve, resulting in quadriceps weakness and reduced strength by up to 50%. Adductor canal nerve block is a possible alternative resulting in less muscle weakness. The rationale behind adductor canal nerve block is blockage of the saphenous nerve and part of the obturator nerve, providing reliable and adequate pain relief.     

Motor evoked potential study suggesting L5 radiculopathy caused by l1-2 disc herniation: case report

A 38-year-old male was referred because of pain in the left 5th lumbar (L5) root territory. Physical examination found moderate motor weakness in the left extensor hallucis longus (EHL) and the left tibialis anterior muscles. Magnetic resonance imaging found no stenotic lesion between L4-L5, but disc herniation was observed on the left between L1-L2. An L5 nerve root block provided temporary relief of the pain but the left foot weakness was exacerbated. Therefore, surgery was performed. Partial laminectomy and left herniotomy were performed at L1-L2, L2-L3, and L3-L4 with motor evoked potential (MEP) monitoring. The MEP amplitude of the left EHL muscle increased immediately after L1-L2 herniotomy. The MEP amplitude of the right EHL muscle also increased after both laminectomy and herniotomy. The postoperative course was uneventful. The left leg pain and motor weakness disappeared. The patient has been doing fine without recurrence for 12 months. Since the MEP of both left and right EHL muscles improved after the L1-2 herniotomy, circulatory insufficiency might have caused the L5 symptoms. Monitoring of the MEP during the surgery was useful for confirming the responsible lesion and also for predicting the postoperative course.     

Percutaneous radiofrequency lesioning of sensory branches of the obturator and femoral nerves for the treatment of hip joint pain

BACKGROUND AND OBJECTIVES: The sensory innervation of the hip joint includes the sensory articular branches of the obturator and femoral nerves. In this report, we retrospectively evaluated 14 cases in which hip joint pain was treated by percutaneous radiofrequency lesioning of sensory branches of obturator and/or femoral nerves. METHODS: Fourteen patients who had hip joint pain and underwent percutaneous radiofrequency lesioning of sensory branches of obturator and/or femoral nerves were studied. In all cases, intra-articular hip joint block or articular branch block of obturator nerve with local anesthesia was transiently effective. Radiofrequency lesioning was performed at 75 degrees C to 80 degrees C for 90 seconds using an RFG-3B generator and Sluijter-Mehta cannulae kit (Radionics, Burlington, MA) for the obturator nerve in 9 patients and for both the obturator and femoral nerves in 5 patients. To assess pain intensity, a visual analog scale (VAS) was used. RESULTS: The VAS scores before and after the radiofrequency lesioning were 6.8 +/- 0.9 and 2.7 +/- 1.3, respectively. Twelve patients (86%) reported at least 50% relief of pain for 1 to 11 months. There were no side effects or motor weakness observed. CONCLUSIONS: Percutaneous radiofrequency lesioning of sensory branches of the obturator and femoral nerves is an alternative treatment in patients with hip joint pain, especially in those where operation is not applicable.     

Editorial Commentary: Quadratus Lumborum Analgesia for Hip Arthroscopy: The New Kid on the (Nerve) Block

Quadratus lumborum (QL) nerve block is a new technique aimed to improve perioperative analgesia for patients undergoing hip arthroscopy. The QL block targets nerve roots from the lumbar plexus supplying the hip and is an alternative to the fascia iliaca compartment block, which has been shown to have variable effects on pain control while increasing motor weakness and postoperative fall risk. Although a recent Level I study showed decreased opioid consumption without increased motor weakness after QL block compared to sham block, another Level I study reported contrasting results with QL block demonstrating no improvement in pain control or opioid consumption compared to a multimodal pain regime after hip arthroscopy. These differing conclusions from high-level studies indicate further research is needed for QL block and that investigation of other potential nerve block options for hip arthroscopy patients, such as the PENG block, is warranted.     

Congenital absence of lumbosacral articular facet joint associated with conjoined nerve root: a case report

We report a rare case of congenital absence of the L5-S1 facet joint, which was associated with a conjoined nerve root. Combination of these two anomalies has been quite rarely reported in the literature. A 39-year-old man presented with acute low back pain and right leg radiating pain. Muscle weakness and sensory disturbance of the right leg were also apparent in the region innervated by L5 and S1 nerve roots. Preoperative multidetector three-dimensional computed tomography (3D-CT) showed complete absence of the right S1 superior articular process. Magnetic resonance (MR) images showed lumbar disc herniation at right L5-S1 level that migrated cranially. Intraoperative findings revealed that the right L5 nerve root and S1 nerve root were conjoined, and the conjoined nerve root was compressed by L5-S1 disc herniation, which led to impairment of the conjoined nerve root by a single-level lumbar disc herniation. After removal of the disc herniation, his right leg pain immediately subsided, however muscle weakness and sensory disturbance persisted. Surgeons should be aware of this nerve root anomaly when examining a patient who shows an unusual clinical presentation and/or congenital osseous anomaly.     

Convulsions following regional hip blockade with bupivacaine and adrenaline

Four out of 100 patients undergoing regional hip block (obturator nerve and nerve to obturator femoris) developed convulsions. These followed the injection of bupivacaine to block the nerve to the quadratus femoris muscle. The reasons for this are discussed. Not only has hip nerve regional blockade been shown to be ineffective in the relief of chronic pain of osteoarthritis but it must be concluded that the method described carries an unacceptably high morbidity.     

Ultrasound-guided obturator nerve block

We reviewed the technique and anatomy for the ultrasound-guided obturator nerve block, especially interadductor approach. Although it is sometimes difficult to observe obturator nerve in the ultrasound image, obturator nerve block is completed observing three muscle layers, adductor longus muscle, adductor blevis muscle and adductor magnus muscle, in the ultrasound image. Local anesthetics are injected between the muscle layers confirming the needle tip and spread of the solution. This technique will reduce incomplete effect or side effects of the obturator nerve block.     

An evaluation of the cutaneous distribution after obturator nerve block.

In 1973, Winnie et al. introduced the inguinal paravascular three-in-one block, which allegedly provides anesthesia of three nerves--the femoral, lateral cutaneous femoral, and obturator nerves--with a single injection. This concept was undisputed until the success of the obturator nerve block was reassessed by using evidence of adductor weakness rather than cutaneous sensory blockade, the latter being variable in its distribution and often absent. We performed this study, therefore, to evaluate the area of sensory loss produced by direct injection of local anesthetic around the obturator nerve. A selective obturator nerve block with 7 mL of 0.75% ropivacaine was performed in 30 patients scheduled for knee surgery. Sensory deficit and adductor strength were evaluated for 30 min by using sensory tests (cold and light-touch perception) and the pressure generated by the patient's squeezing a blood pressure cuff placed between the knees. Subsequently, a three-in-one block was performed, and the sensory deficit was reassessed. The obturator nerve block was successful in 100% of cases. The strength of adductors decreased by 77% +/- 17% (mean +/- SD). In 17 patients (57%), there was no cutaneous contribution of the obturator nerve. The remaining 7 patients (23%) had an area of hypoesthesia (cold sensation was blunt but still present) on the superior part of the popliteal fossa, and the other 6 (20%) had sensory deficit located at the medial aspect of the thigh. The three-in-one block resulted in blockade of the lateral aspect of the thigh in 87% of cases, whereas the anteromedial aspect was always anesthetized. By use of magnetic resonance imaging in eight volunteers, we demonstrated that the obturator nerve has already divided into its two branches at the site of local anesthetic injection. However, the injection of blue dye after having simulated the technique in five cadavers showed that the fluid regularly spread to both branches. We conclude that after three-in-one block, a femoral nerve block may have been assessed as an obturator nerve block in 100% of cases when testing the cutaneous distribution of the obturator nerve on the medial aspect of the thigh. IMPLICATIONS: Previous studies reporting an incidence of obturator nerve block after three-in-one block may have mistaken a femoral nerve block for an obturator nerve block in 100% of cases when the cutaneous distribution of the obturator nerve was assessed on the medial aspect of the thigh. The only way to effectively evaluate obturator nerve function is to assess adductor strength.     

闭孔神经移位修复腰骶丛神经根撕脱伤的解剖学观察及临床应用

目的 观察闭孔神经移位修复腰骶丛神经根撕脱伤的可行性及临床疗效.方法 取15具成人尸体标本,显露双侧闭孔神经及腰骶丛神经根.测量闭孔神经从主干起始部至闭孔入口处的长度及其在闭孔入口处的横径和纵径,计算横截面积,并在高倍显微镜下计数有髓神经纤维数目.以相同方法测量并计算股神经相应指标.2002年1月至2007年9月,共为5例腰骶丛损伤患者进行闭孔神经移位术.行健侧闭孔神经经椎体前腹膜后通路移位与患侧股神经直接吻合4例,闭孔神经移位与同侧S1神经根直接吻合1例.结果 闭孔神经的平均长度为(10.51±0.9)cm,横径(2.03±0.37)mm,纵径(2.78±0.29)mm,有髓神经纤维数目(5974±1996)根;股神经横径(3.79±0.58)mm,纵径(6.53±0.61)mm,有髓神经纤维数目(15 860±4350)根.术后3～7 d,所有患者供肢内收肌肌力均减弱至2～3级;术后3个月,4级2例,3级2例,2级1例(至术后1年时,内收肌肌力恢复3级).4例修复患侧股神经的患者,术后分别随访8个月～5年,股四头肌肌力4级2例,2级1例,1级1例;1例行闭孔神经移位与同侧S1神经根直接吻合的患者,术后11个月时小腿三头肌及屈趾肌肌力恢复至3级.结论 闭孔神经可作为一个安全有效的动力神经源,用其修复腰骶丛神经根撕脱伤可获得满意疗效.     

Magnetic resonance imaging of the distribution of local anesthetic during the three-in-one block

The three-in-one technique of simultaneously blocking the femoral, the lateral femoral cutaneous (LFC), and the obturator nerves by a single injection of a local anesthetic was first described in 1973, and it was suggested that the underlying mechanism was one of cephalad spread resulting in a blockade of the lumbar plexus. Today, the technique is widely used in surgery and pain management of the lower limb. Many investigators have, however, reported suboptimal analgesia levels, particularly in the obturator nerve. The purpose of this prospective study was to trace the distribution of a local anesthetic during a three-in-one block by means of magnetic resonance imaging (MRI). Seven patients scheduled for surgery of the lower limb were analyzed with the aid of a primary MRI and then received three-in-one blocks using 30 mL of bupivacaine 0.5% under the guidance of a nerve stimulator. A secondary MRI was performed to determine the distribution pattern of the local anesthetic. It emerged that the local anesthetic blocks the femoral nerve directly, the LFC nerve through lateral spread, and the anterior branch of the obturator nerve by slightly spreading in a medial direction. No involvement of the proximal and posterior portions of the obturator nerve was observed, nor was there any cephalad spread that could have resulted in a lumbar plexus blockade. We therefore conclude that the basis of the three-in-one block is confined to lateral, medial, and caudal spread of the local anesthetic, which effectively blocks the femoral and LFC nerves, as well as the distal anterior branch of the obturator nerve. IMPLICATIONS: We demonstrate by using magnetic resonance imaging that the mechanism of a three-in-one block is one of lateral, caudal, and slight medial spread of a local anesthetic with subsequent blockade of the femoral, the lateral femoral cutaneous, and the anterior branch of the obturator nerves. It does not involve cephalad spread of the local anesthetic with blockade of the lumbar plexus.     

Neuropathy of the obturator nerve as a source of pain in soccer players]

Chronic inguinal and lower abdominal pain in high-performance athletes is common and often disabling problem. Diagnose and treatment is often difficult due to many anatomic structures in the inguinal and groin region that have the potential to cause pain. We report 52 cases of a chronic groin pain in soccer players due to fascial entrapment of the obturator nerve. All patients presented clinical symptoms and signs of post exercise groin, lower abdominal or medial tight pain and adductor muscles weakness and paresthesia in cutaneous distribution of medial thigh. Except clinical signs in the diagnosis of obturator neuropathy we used diagnostic local anaesthetic block and electromyography. In 52 patients the cause of chronic groin pain was obturator neuropathy and they were treated operatively. Surgical neurolysis provided the definitive cure of pain in 41 players.     

A description of the spread of injectate after psoas compartment block using magnetic resonance imaging

BACKGROUND AND OBJECTIVES: Magnetic resonance imaging (MRI) provides for excellent visualization of spread of solution after peripheral nerve block. The aim of this observational study was to utilize MRI to describe the distribution of injectate (gadopentetate dimeglumine) administered for continuous psoas compartment block (PCB) performed by use of two approaches (Capdevila and modified Winnie) and to describe the spread of injectate to the lumbar plexus. METHODS: Four volunteers were enrolled in a prospective crossover study. Each volunteer underwent PCB with catheter placement performed by use of Capdevila's approach followed 1 week later by PCB, with catheter placement performed by use of a modified Winnie approach. MRI of injectate distribution was performed after each PCB. RESULTS: The catheter was unable to be inserted in 1 volunteer undergoing Winnie's approach; therefore, 7 sets of MR images were analyzed. In 6 of 7 cases (4 Capdevila and 2 Winnie) spread was primarily within the psoas muscle. Contrast surrounded the L2-3 lumbar branch of the femoral nerve at L4 and cleaved the fascial plane within the psoas muscle and spread cephalad to reach the lumbar nerve roots. In 1 case (Winnie approach) contrast spread between the psoas and quadratus lumborum muscles. Contrast surrounded the femoral and obturator nerves where they lie outside the psoas muscle at L5. CONCLUSION: The most common pattern of injectate spread seen on MRI with both approaches to PCB was spread within the body of the psoas muscle around the lumbar branches (L2-4), with cephalad spread to the lumbar nerve roots. One catheter resulted in injectate between the psoas and quadratus lumborum muscles.     

Peripheral nerve blocks for analgesia after elective total hip arthroplasty

A significant subgroup of patients suffer from moderate or severe pain after total hip arthroplasty (THA). Regional analgesia has the potential to reduce post-operative pain and thereby spare patients from opioids, but regional analgesia of the hip is complicated as the area is innervated by multiple nerves. However, the nociceptors of the hip joint are primarily innervated by the obturator and femoral nerves. The effect of an obturator nerve block (ONB) on pain following THA has never been investigated. A femoral nerve block is known to reduce pain after THA, but is unfortunately accompanied by an increased risk of fall. We have developed a novel nerve block—the iliopsoas plane block (IPB)—that has the potential to anaesthetize the hip articular sensory branches of the femoral nerve without causing motor blockade.     

Blockade of the obturator nerve in transurethral electroresection of urinary bladder tumors

Stimulation of obturator nerve during transurethral electroresection causes violent adductor muscle contraction, and is a major cause of inadvertent bladder perforation. General anesthesia with muscle relaxants is often required when the bladder tumor is in the area where the obturator nerve passes in close proximity to the inferolateral bladder wall. Recently obturator nerve block under spinal anesthesia during transurethral surgery have been reported in several papers, but the blockade is not completely reliable. Obturator nerve block using electrostimulator (neutracer) and insulated electroneedle (pole needle) was performed in 25 patients with bladder tumors during transurethral electroresection from October 1980 to December 1981. We herein describe the technique and results of local obturator nerve blockade. Use of neutracer and pole needle makes the obturator nerve block a completely reliable, safe and easy procedure.     

Les sciatiques de la fesse

Confusion between radicular and nerve trunk syndrome is not rare. With sciatic pain, any nerve trunk pain or an atypical nerve course should suggest nerve trunk pain of the sciatic nerve in the buttocks. The usual reflex with sciatic pain is vertebral-radicular conflict. The absence of spinal symptoms and the beginning of pain in the buttocks and not in the lumbar region should reorient the etiologic search.Once a tumor of the nerve trunk has been ruled out (rarely responsible for pain other than that caused by tumor pressure), a myofascial syndrome should be explored searching for clinical, electrophysiological, and radiological evidence of compression of the sciatic trunk by the piriform muscle but also the obturator internus muscle.Hamstring syndrome may be confused with this syndrome.Treatment is first and foremost physical therapy. Failures can be treated with classical CT-guided infiltrations with botulinum toxin.Surgery should only be entertained when all these solutions have failed.     

Continuous three-in-one block for postoperative pain after lower limb orthopedic surgery: where do the catheters go?

Continuous three-in-one block is widely used for postoperative analgesia after proximal lower limb surgery, but location of the catheter has not been well addressed in the literature. We prospectively studied, in 100 patients, the characteristics of catheter threading under the iliac fascia and the correlations between catheter tip location and effective sensory and motor blockade of the three principal nerves of the lumbar plexus. Postoperatively, in conscious patients, 16 to 20 cm of a catheter was placed in the fascial sheath after femoral nerve location with a nerve stimulator. Contrast media (3 mL Iopamidol 390) was injected, and the catheter tip was located by means of an anteroposterior pelvic radiograph. An equal-volume mixture of 0.5% bupivacaine/2% lidocaine with epinephrine (30 mL) was injected through the catheter. Patient and catheter-insertion characteristics were noted. Thirty minutes after injection, sensory blockade was evaluated in the cutaneous territories of the lateral femoral cutaneous, femoral, and obturator nerves, along with motor blockade of the last two nerves. Pain scores at 30 min were also recorded. Seven block failures were noted. The tip of the catheter reached the lumbar plexus (Group 1) in 23% of the patients and lay deep to the medial (Group 2) or lateral (Group 3) part of the fascia iliaca in 33% and 37% of the patients, respectively. Demographic data and catheter threading characteristics were comparable among the groups. A three-in-one block was noted in 91% of Group 1 patients, but in only 52% and 27% of Group 2 and 3 patients, respectively (P < 0.05). Comparing Group 2 and 3 patients, sensory block was achieved in respectively 100% and 94% for the femoral nerve, 52% and 94% for the lateral femoral cutaneous nerve (P < 0.05), and 82% and 27% for the obturator nerve (P < 0.05). Visual analog scale pain scores on movement were significantly lower in Group 1 patients (P < 0.05). We conclude that during a continuous three-in-one block, the threaded catheter rarely reached the lumbar plexus. The quality of sensory and motor blockade and initial pain relief depend on the location of the catheter tip under the fascia iliaca. IMPLICATIONS: The course of a continuous three-in-one block catheter is unpredictable. Only 23% of the catheters lie near the lumbar plexus. The success of sensory and motor blocks, as well as postoperative analgesia, depend on the position of the catheter under the fascia iliaca.     

A new inguinal approach for the obturator nerve block: anatomical and randomized clinical studies

BACKGROUND: Obturator nerve block is highly recommended for knee surgery in addition to a femoral nerve block. The main disadvantage of the classic approach at the pubic tubercle is low patient acceptance due to pain and discomfort. The authors hypothesized that the use of a new inguinal obturator nerve block technique would reduce pain and discomfort in patients. METHODS: The inguinal approach was simulated in five fresh cadavers. Injection of latex was performed in two cadavers. The location of the needle and the extent of latex solution were analyzed. Fifty patients scheduled to undergo arthroscopic knee surgery were randomly assigned to receive obturator nerve block using either the inguinal (n = 25) or the pubic tubercle approach (n = 25). RESULTS: In all cadavers, the needle was close to the obturator nerve branches, which were surrounded by the latex solution. In the clinical study, visual analog scale pain scores and discomfort of block placement were significantly lower in the inguinal group compared with the pubic tubercle group (P < 0.01). In the inguinal group, there was a significant decrease in block performance time (P < 0.05) and in bolus of propofol and fentanyl used for the procedure (P < 0.01). Twenty minutes after application of the block, adductor strength decrease, occurrence, and location of cutaneous distribution of the obturator nerve were not significantly different between the groups. The incidence of minor complications was significantly increased in the pubic tubercle group (P < 0.05). No major complications were observed. CONCLUSIONS: The new inguinal approach decreases patient discomfort and pain of block placement as well as the time and sedation and analgesics required for a similar quality of sensory and motor block compared with the pubic tubercle approach.     

Renal carcinoma relapse presenting as a peripheral nerve sheath tumor: A case report and brief review of the literature

We report a rare case of renal carcinoma metastasis involving a lumbar nerve root. Metastases to nerve roots are rare occurrences, and to our knowledge, only six cases have been reported so far in the literature. The patient in this report presented with weakness in the right lower limb and intractable pain irradiating along the L5 dermatome. MRI findings revealed a right-sided L5 nerve root mass, suggestive of a schwannoma, involving the spinal ganglion and its extraforaminal region. Complete macroscopic resection of this mass was performed, and histopathologic analysis confirmed the lesion to be a metastasis of a renal clear cell carcinoma. Local radiotherapy was given and tyrosine kinase inhibitors administered. At 5 months, the patient was pain-free and his right limb weakness had completely resolved. A tumoral recurrence could be observed on the control MRI 5 months after surgery. This report presents the first case of a patient with a renal clear cell carcinoma metastasis to a L5 nerve root, as well as a brief review of previous cases of metastases to peripheral nerve roots.     

Continuous adductor-canal-blockade for adjuvant post-operative analgesia after major knee surgery: preliminary results

Because both the saphenous nerve and in part the obturator nerve are traversing the adductor canal of the thigh, we hypothesised that repeated administration of a local anaesthetic (LA) into this aponeurotic space could be a useful option for post-operative analgesia after knee replacement surgery. A systematic search of the literature pertinent to the blockade of the saphenous and/or obturator nerves for pain relief after knee surgery was conducted. Further, pain and opioid requirements were evaluated in eight patients receiving a continuous blockade of the saphenous and obturator nerve (adductor-canal-blockade) after total knee arthroplasty (TKA). Finally, we performed cross-sectional MR scans of the adductor canal after injection of ropivacaine 30ml in one patient. The systematic literature search revealed only one controlled study, where selective blockade of the saphenous nerve was investigated for the purpose of clinical pain relief after knee arthroscopy. We located no studies reporting on saphenous and/or obturator nerve block for pain relief after TKA. Preliminary findings in eight patients demonstrated that a continuous adductor-canal-blockade for 48h after TKA was associated with low mean pain scores at rest and low mean requirements for supplemental morphine. MR scans in one patient demonstrated that 30ml of LA filled the adductor canal, including the distal part, where the posterior branch of the obturator nerve joins the vessels and the saphenous nerve. Continuous adductor-canal-blockade may be a valuable adjunct for post-operative analgesia after major knee surgery. These preliminary results should be confirmed in randomised, controlled trials.