The Anatomical Course of the Femoral Nerve with Regard to the Direct Anterior Approach for Total Hip Arthroplasty

BACKGROUND

Femoral nerve (FN) injury is noted as a serious neurological complication following total hip arthroplasty performed via a direct anterior approach (DAA). Therefore, we aimed to clarify the anatomical course of the FN around the acetabular rim and in relation to retractor placement during DAA.

METHODS

According to standard protocol, a DAA for total hip arthroplasty was performed on 69 hemipelves from formalin-preserved full-body donors. The surgery was halted after retractor placement at the anterior part of the acetabulum. Then dissection was performed to expose the FN and the iliopsoas muscle. Various measurements were taken using a reference line from the anterior superior iliac spine to the acetabulum's center. A total of 6 measurement points, one every 30° from 0° to 150° along the reference line were used to determine the association between the FN and the retractor tip (RT) and the anterior acetabular rim.

RESULTS

The mean distance from the RT to the FN was 22.5 millimeters (mm). The distance from the FN to the anterior acetabular rim decreased from 0 to 90°, where it was 18.8 mm, before increasing again to 27.3 mm at 150°.

CONCLUSIONS

In our cadaveric study, the FN was within 11 to 36 mm of the RT. Second, we found the FN to be closest to the anterior acetabular rim at 90° and 120°. Accordingly, special care should be taken during retractor placement, and if possible, placement at 90° and 120° avoided.

Percutaneous pulsed radiofrequency ablation of articular nerves of the hip joint in patients with chronic hip pain refractory to conventional analgesics

OBJECTIVES

Total Hip Arthroplasty (THA) may be a risky proposition in patients with comorbidities, and they may require systemic analgesics for chronic hip pain (CHP). Since traditional pain medications may not provide complete pain relief or carry prohibitive adverse effects, pulsed radiofrequency (PRF) treatment of the hip articular nerves (HAN) has been proposed for effective clinical outcomes. We determined the efficacy of PRF-HAN in improvement in CHP compared to baseline pain on conventional systemic analgesics.

METHODS

Between August 2015 and December 2021, 31 adult patients with severe comorbid conditions and excruciating chronic hip pain were subjected to a PRF-HAN procedure following a diagnostic block. All 31 patients received PRF of the articular branches of the femoral and obturator nerves. Demographic parameters, numerical rating scale (NRS), Harris Hip Score (HHS), WOMAC scores, the change of these scores from baseline, and any adverse effects were recorded before treatment and on day 1, 1st week, 6 weeks, and 6 months after treatment.

RESULTS

All the patients who underwent the PRF-HAN reported a significant improvement in NRS, HHS, and WOMAC scores compared to the baseline values on day 1, at the end of the 1st week, and the 6th week (p<0.001). No adverse events were documented in the study post-procedure until the end of 6 months.

CONCLUSION

PRF-HAN is a strong alternative for chronic pain management and augments physical functioning and a return to daily activity in patients who would be deprived of arthroplasty considering associated comorbid conditions.

Analgesic efficacy of local infiltration anaesthesia versus femoral nerve block in alleviating postoperative wound pain following total knee arthroplasty: A systematic review and meta-analysis

Total knee arthroplasty (TKA) often involves significant postoperative pain, necessitating effective analgesia. This meta-analysis compares the analgesic efficacy of local infiltration anaesthesia (LIA) and femoral nerve block (FNB) in managing postoperative wound pain following TKA. Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, this meta-analysis was structured around the PICO framework, assessing studies that directly compared LIA and FNB in TKA patients. A comprehensive search across PubMed, Embase, Web of Science and the Cochrane Library was conducted without time restrictions. Studies were included based on specific criteria such as participant demographics, study design and outcomes like pain scores and opioid consumption. Quality assessment utilized the Cochrane Collaboration's risk of bias tool. The statistical approach was determined based on heterogeneity, with the choice of fixed- or random-effects models guided by the I2 statistic. Sensitivity analysis and evaluation of publication bias using funnel plots and Egger's linear regression test were also conducted. From an initial pool of 1275 articles, eight studies met the inclusion criteria. These studies conducted in various countries from 2007 to 2016. The meta-analysis showed no significant difference in resting and movement-related Visual Analogue Scale scores post-TKA between the LIA and FNB groups. However, LIA was associated with significantly lower opioid consumption. The quality assessment revealed a low risk of bias in most studies, and the sensitivity analysis confirmed the stability of these findings. There was no significant publication bias detected. Both LIA and FNB are effective in controlling postoperative pain in TKA patients, but LIA offers the advantage of lower opioid consumption. Its simplicity, cost-effectiveness and opioid-sparing nature make LIA the recommended choice for postoperative analgesia in knee replacement surgeries.

[Femoral nerve repair with autografts for proximal retroperitoneal damage (case report and literature review)]

Femoral nerve damage, especially in proximal retroperitoneal space, is rare. Therefore, surgical strategy is still unclear for these patients. Various specialists discuss repair with autografts or neurotization by the obturator nerve or its muscular branch.

OBJECTIVE

To demonstrate the diagnostic algorithm for proximal femoral nerve injury and favorable outcomes after repair with long autografts.

MATERIAL AND METHODS

We assessed movements and sensitivity using a five-point scale, as well as ultrasound, magnetic resonance imaging and electroneuromyography data in a patient with extended iatrogenic femoral nerve damage before and after repair with long autografts (10.5 cm).

RESULTS AND DISCUSSION

The patient had complete femoral nerve interruption in proximal retroperitoneal space with 10-cm defect that required repair with five autografts from two sural nerves. Postoperative ultrasound and magnetic resonance imaging revealed signs of graft survival and no neuroma within the nerve suture lines. The first signs of motor recovery occurred after 10 months. After 14 months, strength of quadriceps femoris muscle comprised 4 points, and electroneuromyography confirmed re-innervation.

CONCLUSION

Femoral nerve repair with autografts for complete proximal anatomical interruption can provide sufficient restoration of movements and sensitivity. Therefore, this surgical option should be preferred instead of neurotization. Ultrasound, MRI and ENMG are valuable to clarify the diagnosis and state of the autografts.

Surgical course of lateral femoral cutaneous nerve during anterior exposure of paediatric hips: an observational study

Anterior approach to the hip joint is commonly used for paediatric hip disorders. Lateral femoral cutaneous nerve (LFCN) is always exposed and dissected in this approach before deep dissection is carried out. The course of this nerve has been described in adults but there is a lack of literature regarding this in the paediatric age group. This study aimed to find the surgical anatomy of LFCN in children during the anterior approach to the hip. A total of 51 paediatric hip surgeries were done in 45 children for various hip disorders. The anterior exposure was done by the Somerville approach (Bikini incision). During surgical exposure, LFCN was exposed and its relationship to anterior superior iliac spine (ASIS), inguinal ligament and sartorius muscle was observed. In most of the cases (45/51) it was found as a single trunk below the inguinal ligament and medial to the ASIS. In one hip, multiple branches of the nerve were found just below the inguinal ligament. In four hip exposures, the nerve was not found in the surgical field and in one case nerve was accidentally cut during surgery as it was lying adherent to ASIS. There was no significant correlation between the observational parameters of the nerve with anthropometric variables. Nerve was mostly seen in area 5-25 mm medial to ASIS and 10-50 mm below the ASIS in 80% of our surgical exposures where the nerve was isolated. We observed that once LFCN is dissected, the injury during further surgical procedures can be prevented.

Surgical anatomy of the lateral femoral cutaneous nerve for meralgia paraesthetica: A simple technical guide for surgeons and trainees alike

Meralgia paraesthetica is an entrapment neuropathy of the lateral femoral cutaneous nerve, usually due to compression at the inguinal ligament as the nerve passes from the pelvis into the thigh. Surgical decompression of the lateral femoral cutaneous nerve is a simple and effective treatment option, but the surgical anatomy of the area is not always familiar to neurosurgeons and neurosurgical trainees alike. This paper is a simple review of the relevant surgical anatomy and the surgical steps of lateral femoral cutaneous nerve decompression, with the aim of providing the busy surgeon and trainee a quick and easy reference guide to the procedure.

Effects of thigh extension on the position of the femoral nerve: application to prone lateral transpsoas approaches to the lumbar spine

Some authors have suggested that thigh extension during the prone lateral transpsoas approach to the lumbar spine provides the theoretical advantage of providing posterior shift of the psoas muscle and plexus and is responsible for its lower rates of nerve injury. We aimed to elucidate the effects of surgical positioning on the femoral nerve within the psoas muscle via a cadaveric study. In the supine position, 10 fresh frozen adult cadavers had a metal wire secured to the pelvic segment of the femoral nerve and then extended proximally along with its L2 contribution. Fluoroscopy was then used to identify the wires on the femoral nerves in a neutral position and with the thigh extended and flexed by 25 and 45°. Additionally, a lateral incision was made in the anterolateral abdominal wall to mimic a lateral transpsoas approach to the lumbar spine, and measurements were made of the amount of movement in the vertical plane of the femoral nerve from neutral to then 25 and 45° of thigh flexion and extension. On fluoroscopy, the femoral nerves moved posteriorly at a mean of 10.1 mm with thigh extension. Femoral nerve movement could not be detected at any degree of this range of flexion of the thigh. Extension of the thigh to about 30° can move the femoral nerve farther away from the dissection plane by approximately one centimeter. This hip extension not only places the femoral nerve in a more advantageous position for lateral lumbar interbody fusion procedures but also helps to promote accentuation of lumbar lordosis.

A Cadaveric Study Measuring Femoral Nerve Tension During Anterior Total Hip Arthroplasty Approach

Femoral nerve palsy is a rare but devastating complication of anterior total hip arthroplasty. Its etiology is still unknown, but several studies have suggested that anterior acetabular retractors may place the femoral nerve at increased risk. This study hypothesized that hip extension and traction places tension on the femoral nerve, offering an additional explanation for the development of femoral nerve palsy. A spring device was secured across 6 transected femoral nerves from 5 lower extremity cadavers and the hip was extended and pulled into traction with and without retractor placement. The change in spring length was used to determine femoral nerve tension. The average spring length changed +8.83 mm with hip extension, +3.73 mm with traction, -0.7 mm with traction and placement of the anterior acetabular retractor, and -1.15 mm with extension and placement of the femoral retractor. Femoral nerve tension was greatest with hip extension followed by traction. Acetabular and femoral retractor placement decreased average femoral nerve tension in both traction and hip extension. This may be due to medialization of the femoral nerve by the retractors, reducing the overall distance traveled, and thereby reducing tension. Previous studies have found femoral nerve pressure to be greatest during anterior acetabular retractor placement. It is likely that both pressure and tension contribute to femoral nerve palsy. Careful retractor placement, staying safely on anterior acetabular bone, and efficient femoral preparation to decrease time under hip extension and traction may help to minimize the risk of femoral nerve palsy.

Cooled Radiofrequency Ablation of the Articular Sensory Branches of the Obturator and Femoral Nerves using Fluoroscopy and Ultrasound Guidance: A Large Retrospective Study

BACKGROUND

We previously reported on a combined technique and initial data of hip denervation using an anterior approach and cooled radiofrequency.

OBJECTIVES

A large retrospective study to evaluate the long-term effectiveness of cooled radiofrequency ablation (CRFA) in the general chronic hip pain population.

STUDY DESIGN

Retrospective electronic chart review.

SETTING

A single specialty private practice.

METHODS

Retrospective chart review of 235 consecutive (CRFA) in 136 patients with chronic hip pain.

RESULTS

Out of 235 CRFA, 178 (96 initial procedures and 82 repeats) were performed in 84 patients with 12 or more months follow-up. The average decrease in visual analog scale (VAS) pain scores was 7.3 ± 1.3 to 2.3 ± 1.5 and 2.48 ± 1.5 for the first and second diagnostic block, respectively, and was statistically significant (P < 0.001). Similarly, the average decrease in VAS pain scores at 6 and 12 months after CRFA denervation was 3.44 ± 2.5 and 4.23 ± 2.5, respectively; P < 0.001. Out of the 96 initial procedures in 84 patients, 66 procedures (69%) provided more than 50% relief at 6 months, and 50 (52%) at 12 months. There were 82 repeat denervations in 36 patients. Repeated procedures in the same patients provided a similar degree of pain relief with no statistically significant difference in the median pain scores (2.8 ± 2.1 cm vs 3.1 ± 1.7 cm ; P = 0.197) or time interval of pain relief (12.7 ± 10.9 vs 10.3 ± 4.7;  P = 0.508). There were 3 minor complications.

LIMITATIONS

Retrospective nature of the study.

CONCLUSION

Improvements in pain scores and longevity of pain relief from chronic hip pain using a simple, anterior approach to radiofrequency denervation of the lateral obturator and lateral femoral nerves justifies further randomized prospective trials. Repeated CRFAs demonstrated consistency in pain relief and absolute safety of repeated denervation.

Erectile Functional Restoration With Genital Branch of Genitofemoral Nerve to Pelvic Nerve Transfer After Spinal Root Transection in Rats

OBJECTIVE

To investigate the feasibility of erectile function restoration by the genitofemoral nerve to pelvic nerve transfer in rats.

METHODS

Thirty-six male rats were included in this study. Rats in the nerve transfer group (n = 12) were subjected to pelvic nerve, sacral roots, and L6 roots transection and then bilateral genitofemoral nerve to pelvic nerve transfer, rats in the nerve resection group (n = 12) were subjected to pelvic nerve, sacral roots, and L6 roots transection without nerve transfer, and rats in the control group (n = 12) served as controls. After reinnervation, intracavernous pressure (ICP) assessment was performed. Fluoro-Gold was injected into the corpus cavernosum. Immediately before euthanasia, transferred nerves were stimulated to test penile intracavernous pressure. The L6, S1, and L1-2 spinal cord segments were used for retrogradely labeled neurons. Regenerative nerve morphologic examination assessment was performed.

RESULTS

Genitofemoral nerve stimulation induced an increase in ICP in the nerve transfer group. The mean ICP in this group was (33.8 ± 9.4 mm Hg), which is higher than the mean value in the nerve resection group (3.9 ± 1.0 mm Hg) but lower than that in the control group (69.8 ± 12.2 mm Hg; P < .05). The formation of new neural pathways was confirmed by the appearance of Fluoro-Gold labeled neurons in the L-1 and L-2 spinal cord segments in the nerve transfer group. Regenerative nerve morphologic examination showed good axonal regeneration after genitofemoral nerve transfer.

CONCLUSION

Nerve regeneration can be obtained by genitofemoral nerve to pelvic nerve transfer, and erectile function can be restored.

Minimally Invasive Therapies for Osteoarthritic Hip Pain: a Comprehensive Review

PURPOSE OF REVIEW

Osteoarthritis (OA) is a highly prevalent cause of chronic hip pain, affecting 27% of adults aged over 45 years and 42% of adults aged over 75 years. Though OA has traditionally been described as a disorder of "wear-and-tear," recent studies have expanded on this understanding to include a possible inflammatory etiology as well, damage to articular cartilage produces debris in the joint that is phagocytosed by synovial cells which leads to inflammation.

RECENT FINDINGS

Patients with OA of the hip frequently have decreased quality of life due to pain and limited mobility though additional comorbidities of diabetes, cardiovascular disease, poor sleep quality, and obesity have been correlated. Initial treatment with conservative medical management can provide effective symptomatic relief. Physical therapy and exercise are important components of a multimodal approach to osteoarthritic hip pain. Patients with persistent pain may benefit from minimally invasive therapeutic approaches prior to consideration of undergoing total hip arthroplasty. The objective of this review is to provide an update of current minimally invasive therapies for the treatment of pain stemming from hip osteoarthritis; these include intra-articular injection of medication, regenerative therapies, and radiofrequency ablation.

Transferring of femoral nerve motor branches for high-level sciatic nerve injury: a cadaver feasibility study

BACKGROUND

Sciatic nerve injuries cause significant disability. We propose here a novel reconstructive procedure of transferring the motor branches of the femoral nerve as donor nerves to reconstruct both the peroneal and tibial nerve function as a novel approach to treat high sciatic nerve injury.

METHODS

The autopsies of donor nerves (vastus lateralis nerve branch (VLN), vastus medialis nerve branch (VMN), saphenous nerve (SAN)) and respective recipient nerves (deep peroneal nerve branch (DPN), medial gastrocnemius nerve branch (MGN), sural nerve (SN)) were conducted in six fresh-frozen lower limbs. The distance between the origin or bifurcation points of the nerves to the head of fibula and the diameter of the end at the coaptation site were measured. The feasibility of tensionless direct suturing or grafting between the donor nerves and the recipient was evaluated. Finally, the nerve end at the coaptation site was harvested for observation with toluidine blue staining and nerve fiber count.

RESULTS

The mean diameter of the VMN, VLN, MGN, DPN, SAN, and SN nerves were 1.5 ± 0.1, 1.4 ± 0.1, 1.3 ± 0.1, 2.3 ± 0.1, 2.1 ± 0.3, and 1.3 ± 0.2 mm, respectively. Histological observation showed that the abovementioned six nerve bundles had a respective nerve fiber number of 392 ± 27, 205 ± 520, 219 ± 67, 394 ± 50, 308 ± 77, and 335 ± 49. A total of 5/6 specimens needed grafting for a length ranging from 5 to 15 cm to bridge the VMN-MGN, 6/6 needed a graft length of 10-20 cm for VLN-DPN bridging, and 2/6 needed a graft length of 0-4 cm for SAN-SN bridging.

CONCLUSION

The study demonstrated the feasibility of the transferring femoral nerve branches to sciatic nerve branches to restore the function for sciatic injury.

Surgical decompression of the lateral femoral cutaneous nerve (LFCN) for Meralgia paresthetica treatment: Experimental or state of the art? A single-center outcome analysis

Meralgia paresthetica (MP) is a rare lateral femoral cutaneous nerve-(LFCN)-mononeuropathy. Treatment for this disorder includes conservative and operative approaches; the latter is considered if conservative therapy fails. The most commonly used surgical approaches are decompression/neurolysis and avulsion/neurectomy. However, there are no definitive guidelines on the optimal surgical approach to be used. The purpose of this study was to evaluate the outcome of surgical decompression of the LFCN for the treatment of persistent MP with preservation of sensation along the distribution of the LFCN.We evaluated the outcomes of LFCN procedures performed between 2015 and 2016. A total of 16 surgical decompressions could be identified. Retrospective analysis of prospectively collected patient data was performed, as well as systematic evaluation of the postoperative course, with regular follow-up examinations based on a standardized protocol. Pain was analyzed using an NRS (numeric rating scale). Several postsurgical parameters, including temperature hypersensitivity and numbness in the LFCN region, were compared with the presurgical data.Sixty-nine percent of patients had histories of trauma or surgery, which were designated as the onset of pain. Of these patients, 78% had hip prostheses, 2 had previous falls. Postoperatively, a significant reduction of 6.6 points in the mean NRS pain value was observed. All other evaluated parameters also improved postoperatively. Patient satisfaction was high, with 86% reporting complete satisfaction, and 14% reporting partial satisfaction.Previous studies favor either avulsion/neurectomy as the preferred procedure for MP treatment, or provide no recommendation. Our findings instead confirm the decompression/neurolysis approach as the primary surgical procedure of choice for the treatment of MP, if conservative treatment fails.

Comparison of Periarticular Local Infiltration Analgesia With Femoral Nerve Block for Total Knee Arthroplasty: a Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Total knee arthroplasty (TKA) is accompanied by moderate-to-severe postoperative pain. Postoperative pain will hamper functional recovery and lower patients' satisfaction with surgery. Recently, periarticular local infiltration analgesia (LIA) has been widely used in TKA. However, there is no definite answer as to the efficacy and safety of LIA compared with femoral nerve block (FNB).

METHOD

Randomized controlled trials about relevant studies were searched from PubMed (1996 to July 2017), Embase (1980 to July 2017), and Cochrane Library (CENTRAL, July 2017). Ten studies which compared LIA with FNB methods were included in our meta-analysis.

RESULTS

Ten studies containing 950 patients met the inclusion criteria. Our pooled data indicated that LIA was as effective as the FNB in terms of visual analog scale score for pain at 24 hours (P = .52), 48 hours (P = .36), and 72 hours (P = .27), and total morphine consumption (P = .27), range of motion (P = .45), knee society score (P = .51), complications (P = .81), and length of hospital stay (P = .75).

CONCLUSIONS

Our current meta-analysis results demonstrated that there were no differences in efficacy between the FNB and LIA method.

Anatomic Variation in Patient with Lateral Femoral Cutaneous Nerve Entrapment Neuropathy

BACKGROUND

We report a surgical case of entrapment neuropathy of lateral femoral cutaneous nerve (LFCN) with anatomical variation.

CASE DESCRIPTION

This 53-year-old man had a 10-year history of paresthesia and pain in the right anterolateral thigh exacerbated by prolonged standing and walking. His symptoms improved completely but transiently by LFCN block. The diagnosis was LFCN entrapment. Because additional treatment with drugs and repeat LFCN block was ineffective, we performed surgical decompression under local anesthesia. A nerve stimulator located the LFCN 4.5 cm medial to the anterior superior iliac spine. It formed a sharp curve and was embedded in connective tissue. Proximal dissection showed it to run parallel to the femoral nerve at the level of the inguinal ligament. The inguinal ligament was partially released to complete dissection/release. Postoperatively, his symptoms improved and the numeric rating scale fell from 8 to 1.

CONCLUSION

We report a rare anatomical variation in the course of the LFCN.

Cooled Radiofrequency Neurotomy of the Articular Sensory Branches of the Obturator and Femoral Nerves - Combined Approach Using Fluoroscopy and Ultrasound Guidance: Technical Report, and Observational Study on Safety and Efficacy

BACKGROUND

Chronic hip joint pain is a common condition with an estimated prevalence of 7% in men and 10% in women, in a population sample aged over 45. Conservative treatment can include physical therapy, weight loss, a variety of pharmacologic agents ranging from nonsteroidal antiinflammatory drugs (NSAIDS) to opioids, and intraarticular injections with various substances. Definitive treatment of hip pain, however, has primarily centered on hip arthroplasty.

OBJECTIVE

We describe a novel anterior approach to cooled radiofrequency (RF) hip denervation under combined ultrasound (US) and fluoroscopy guidance to avoid the neurovascular femoral bundle and reach proper landmarks.

STUDY DESIGN

Retrospective chart review of consecutive cases.

SETTING

Interventional Pain Management urban private practice.

METHODS

Data on 52 RF ablations of the hip in 23 patients were retrospectively collected. RF ablation was conducted with patient supine and under guidance of fluoroscopy and US. While fluoroscopy was used to place RF probes to appropriate landmarks, sole purpose of using US was to avoid femoral neurovascular bundle. Data were collected on needle placement, stimulation parameters, and short- and long-term complications.

RESULTS

A total of 62 patients underwent 2 diagnostic blocks. Fifty-two of them had greater than 50% relief and agreed to RF ablation. Until now, the ablation was conducted in 23 patients. There were no adverse events, except one case of neuritis. Expectedly, the needle approach to the lateral articular branches of the femoral nerve was easily achieved with more than a 1 cm passage distance from the femoral nerve in all 52 RF cases (median 2.5 range 1-3.5 cm). Placement of the second trocar to the incisura acetabuli was more challenging; in 21 RF cases the passing distance was less than 1 cm (range 0.5 to 1.9 cm, median 0.8). Motor stimulation (2 Hz) at less than 1 V was positive for the obturator nerve in 26 cases, which resulted in electrode repositioning more laterally (2-5 mm). Change in the pain scores was from the baseline 7.61 ± 1.2 to 2.25 ± 1.4 after the RF ablation (P < 0.01). The time interval of pain relief was much longer for RF ablation.

LIMITATIONS

Limitations of this retrospective, observational study include lack of blinding and absence of a comparator group. We did not attempt to wean opioids in our patient population.

CONCLUSIONS

An anterior needle approach to the lateral articular branches of the femoral and obturator nerves, and subsequently RF denervation of these nerves, is a safe procedure when US needle guidance is combined with identification of landmarks using fluoroscopy.

KEY WORDS

Chronic hip pain, radiofrequency ablation, hip denervation.

Combined Femoral-Sciatic Nerve Block is Superior to Continuous Femoral Nerve Block During Anterior Cruciate Ligament Reconstruction in the Pediatric Population

BACKGROUND

Despite advancements in minimally invasive arthroscopic surgical techniques, post-operative pain management following ACL reconstruction remains a concern. This study compares the effectiveness of two common intraoperative pain management strategies - a femoral nerve catheter (FC) versus a combined femoral nerve catheter and single injection sciatic nerve block (FSB) - in pediatric patients undergoing ACL reconstruction.

METHODS

The medical records of patients age 8 to 18 who underwent ACL reconstruction at our institution were reviewed retrospectively. All subjects underwent general anesthesia with either FC or FSB. Multivariable linear regression, or modified Poisson regression were used to compare outcome variables across groups. Propensity scores were used to minimize bias due to the non-randomized allocation of the regional anesthesia protocol.

RESULTS

The study population included 18 subjects in the FC group and 32 subjects in the FSB group. There was no difference in incidence of nausea or opioid prescription refill requests between groups. Total intravenous (IV) morphine equivalent dose, maximum numerical rating scale (NRS) pain score, and percentage of subjects requiring one or more opioid doses in the PACU were significantly greater in the FC group relative to the FSB group. PACU length of stay (LOS) was also significantly greater in the FC group than the FSB group.

CONCLUSION

This study suggests that FSB may be a more effective pain management technique for reducing the total IV morphine equivalent dose, maximum NRS pain scores, number of PACU postoperative opioid doses, and PACU LOS following ACL reconstruction in the pediatric population.Level of Evidence: III.

A randomized comparison between neurostimulation and ultrasound-guided lateral femoral cutaneous nerve block

BACKGROUND

This prospective, randomized trial compared neurostimulation (NS) and ultrasound (US) guided lateral femoral cutaneous nerve (LFCN) block. We hypothesized that US would result in a shorter total anesthesia-related time (sum of performance and onset times).

METHODS

Twenty-one volunteers were enrolled. The right lower limb was randomized to an NS- or US-guided LFCN block. The alternate technique was employed for the left lower limb. With NS, paresthesias were sought in the lateral thigh at a stimulatory threshold of 0.6 mA (pulse width=0.3 ms; frequency=2 Hz) or lower. With US, local anesthetic was deposited under the inguinal ligament, ventral to the iliopsoas muscle. In both groups, 5 mL of lidocaine 2% were used to anesthetize the nerve. During the procedure of the block, the performance time and number of needle passes were recorded. Subsequently, a blinded observer assessed sensory block in the lateral thigh every minute until 20 minutes. Success was defined as loss of pinprick sensation at a point midway between the anterior superior iliac spine and the lateral knee line. The blinded observer also assessed the areas of sensory block in the anterior, medial, lateral, and posterior aspects of the thigh and mapped this distribution onto a corresponding grid.

RESULTS

Both modalities provided comparable success rates (76.2%-95.2%), performance times (162.1 to 231.3 seconds), onset times (300.0 to 307.5 seconds) and total anesthesia related-times (480.1 to 554.0 seconds). However US required fewer needle passes (3.2±2.9 vs 9.5±12.2; P=.009). There were no intergroup differences in terms of the distribution of the anesthetized cutaneous areas. However considerable variability was encountered between individuals and between the 2 sides of a same subject. The most common areas of sensory loss included the central lateral two-eighths anteriorly and the central antero-inferior three-eighths laterally.

CONCLUSION

Ultrasound guidance and NS provide similar success rates and total anesthesia-related times for LFCN block. The territory of the LFCN displays wide inter- and intra-individual variability.

Evidence of vagus nerve sprouting to innervate the urinary bladder and clitoris in a canine model of lower motoneuron lesioned bladder

AIMS

Complete spinal cord injury does not block perceptual responses or inferior solitary nucleus activation after genital self-stimulation, even though the vagus is not thought to innervate pelvic structures. We tested if vagus nerve endings sprout after bladder decentralization to innervate genitourinary structures in canines with decentralized bladders.

METHODS

Four reinnervation surgeries were performed in female hounds: bilateral genitofemoral nerve transfer to pelvic nerve with vesicostomy (GNF-V) or without (GFN-NV); and left femoral nerve transfer (FNT-V and FNT-NV). After 8 months, retrograde dyes were injected into genitourinary structures. Three weeks later, at euthanasia, reinnervation was evaluated as increased detrusor pressure induced by functional electrical stimulation (FES). Controls included un-operated, sham-operated, and decentralized animals.

RESULTS

Increased detrusor pressure was seen in 8/12 GFNT-V, 4/5 GFNT-NV, 5/5 FNT-V, and 4/5 FNT-NV animals after FES, but not decentralized controls. Lumbar cord segments contained cells labeled from the bladder in all nerve transfer animals with FES-induced increased detrusor pressure. Nodose ganglia cells labeled from the bladder were observed in 5/7 nerve transfer animals (1/2 GNT-NV; 4/5 FNT-V), and from the clitoris were in 6/7 nerve transfer animals (2/2 GFNT-NV; 4/5 FNT-V). Dorsal motor nucleus vagus cells labeled from the bladder were observed in 3/5 nerve transfer animals (1/2 GFNT-NV; 2/3 FNT-V), and from the clitoris in 4/5 nerve transfer animals (1/2 GFNT-NV; 3/3 FNT-V). Controls lacked this labeling.

CONCLUSIONS

Evidence of vagal nerve sprouting to the bladder and clitoris was observed in canines with lower motoneuron lesioned bladders. Neurourol. Urodynam. 36:91-97, 2017. © 2015 Wiley Periodicals, Inc.

Real-Time Automatic Artery Segmentation, Reconstruction and Registration for Ultrasound-Guided Regional Anaesthesia of the Femoral Nerve

The goal is to create an assistant for ultrasound- guided femoral nerve block. By segmenting and visualizing the important structures such as the femoral artery, we hope to improve the success of these procedures. This article is the first step towards this goal and presents novel real-time methods for identifying and reconstructing the femoral artery, and registering a model of the surrounding anatomy to the ultrasound images. The femoral artery is modelled as an ellipse. The artery is first detected by a novel algorithm which initializes the artery tracking. This algorithm is completely automatic and requires no user interaction. Artery tracking is achieved with a Kalman filter. The 3D artery is reconstructed in real-time with a novel algorithm and a tracked ultrasound probe. A mesh model of the surrounding anatomy was created from a CT dataset. Registration of this model is achieved by landmark registration using the centerpoints from the artery tracking and the femoral artery centerline of the model. The artery detection method was able to automatically detect the femoral artery and initialize the tracking in all 48 ultrasound sequences. The tracking algorithm achieved an average dice similarity coefficient of 0.91, absolute distance of 0.33 mm, and Hausdorff distance 1.05 mm. The mean registration error was 2.7 mm, while the average maximum error was 12.4 mm. The average runtime was measured to be 38, 8, 46 and 0.2 milliseconds for the artery detection, tracking, reconstruction and registration methods respectively.

Laparoscopic Neurolysis of Deep Endometriosis Infiltrating Left Femoral Nerve: Case Report

Pelvic endometriosis may infiltrate somatic nerves causing severe neuropathic symptoms with a high impact on quality of life. It is a medical condition poorly known, and few published data about involvement of femoral nerve are available. We report an isolated unilateral endometriosis lesion of the left lumbar region infiltrating the femoral nerve in a 38-year-old woman. She described severe dysmenorrhea, dyspareunia, dischezia, and chronic pelvic pain with irradiation to the anterior part of the left thigh. After investigation, it was identified as a 5-centimeter endometriotic nodule involving the femoral nerve and the psoas muscle. The patient was treated by two laparoscopic surgeries with neurolysis of the involved somatic nerve by a multidisciplinary team, with improvement of the symptoms. Laparoscopic neurolysis is the first approach advocated in these cases, leading to relief of neurological symptoms resulting from nerve infiltration by endometriosis.

Radiofrequency denervation of the hip joint for pain management: case report and literature review

BACKGROUND

A 55-year-old male presented with severe pain and functional limitations as a result of left hip osteoarthritis. He had failed multiple treatments while waiting for a hip arthroplasty, including physical therapy, medications, and various intra-articular injections. Thermal radiofrequency lesioning of the obturator and femoral articular branches to the hip joint was offered in the interim.

OBJECTIVES

To our knowledge, this is the first report to describe an inferior-lateral approach for lesioning the obturator branch, the clinical application of successive lesions to increase denervation area, and outcomes in a patient receiving a second treatment with previously good results.

METHODS

To discuss relevant and technical factors for this specific case, we reviewed previous literature on hip joint radiofrequency and critically evaluated previous anatomic studies in the context of radiofrequency.

RESULTS

The first treatment provided significant benefit for a period of 6 months. A second treatment was employed providing only mild to moderate benefit until his joint replacement surgery 4 months later. Literature review revealed studies of low quality secondary to small sample sizes, patient selection methodology, inclusion of patients with heterogenous etiologies for pain, variable needle placement techniques, and lack of measurement of functional outcomes.

LIMITATIONS

Case report and low quality studies in existing literature.

CONCLUSIONS

Hip joint radiofrequency denervation is a promising avenue for adjunctive treatment of hip pain. Further cadaveric studies are required to clarify a multitude of technical parameters. Once these are well defined, future clinical studies should consider pain, functional, and economic outcomes in their design.

Current status: new technologies for the treatment of patients with fecal incontinence

Fecal incontinence is a frequent and debilitating condition that may result from a multitude of different causes. Treatment is often challenging and needs to be individualized. During the last several years, new technologies have been developed, and others are emerging from clinical trials to commercialization. Although their specific roles in the management of fecal incontinence have not yet been completely defined, surgeons have access to them and patients may request them. The purpose of this project is to put into perspective, for both the patient and the practitioner, the relative positions of new and emerging technologies in order to propose a treatment algorithm.

Southwick-Fulkerson Osteotomy with intraoperative femoral nerve guidance

BACKGROUND

Patellofemoral instability is a complex problem with most previous treatment plans addressing static alignment and static stabilizers. Although the quadriceps muscles are known to affect the tracking of the patella, they are rarely taken into account during a surgical procedure.

PURPOSE

The purpose of this study is to determine the two year minimum results of 37 knees which received a Southwick-Fulkerson Osteotomy and MPFL repair or reconstruction both under the guidance of femoral nerve stimulation.

METHODS

Patients underwent a Southwick-Fulkerson Osteotomy and either medial patellofemoral ligament (MPFL) repair or reconstruction using femoral nerve stimulation as a means of dynamic intraoperative evaluation of patello-femoral congruity in terminal extension. Two year minimum outcomes of 26 patients, 31 knees (84% return rate) were evaluated using KOOS and IKDC scores, and physical exam features of apprehension and assessment of dynamic tracking in the last 30 degrees of knee extension. Variables were evaluated with t-tests and ANOVA.

RESULTS

29/31 knees reported they were happy with the procedure and reported they would do it again. One knee (3%) reportedly "redislocated", but did not return for verification by exam. 30/31 had non-pathologic tracking. One knee displayed a small but residual J sign. 4/16 knees with MPFL repair only and 0/15 with MPFL repair and reconstruction exhibited a positive apprehension sign. Increased age and apprehension were correlated with lower outcome scores.

CONCLUSIONS

Intraoperative femoral nerve stimulation is an effective way of evaluating patellar tracking intraoperatively that leads to 97% stable patellae with near congruent patello-femoral tracking. MPFL reconstruction is superior to MPFL repair in eliminating the persistence of the apprehension sign.

Treatment for meralgia paraesthetica

BACKGROUND

Meralgia paraesthetica is a clinical syndrome for which a number of treatments are in common use, including conservative measures, injection of corticosteroid with local anaesthetic and surgery. We aimed to examine the evidence for the relative efficacy of these interventions. This review was first published in 2008. Searches were updated in 2010 and 2012.

OBJECTIVES

To assess the relative efficacy of commonly used treatments for meralgia paraesthetica.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialized Register (1 October 2012), CENTRAL (2012, issue 9 in The Cochrane Library), MEDLINE (January 1966 to October 2012), EMBASE (January 1980 to October 2012) and CINAHL Plus (January 1937 to October 2012) for randomised controlled studies. Non-randomised studies were identified by searching MEDLINE (January 1966 to October 2012) and EMBASE (January 1980 to October 2012). We also inspected the reference lists of these studies.

SELECTION CRITERIA

We were unable to identify any randomised controlled trials (RCTs) or quasi-RCTs. We therefore looked for high quality observational studies meeting the following criteria: (1) At least five cases of meralgia paraesthetica. (2) Follow-up of at least three months after intervention (if any). (3) At least 80% of cases followed up.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted relevant data from each study meeting the selection criteria and transferred into a data extraction form.

MAIN RESULTS

We found no RCTs or quasi-RCTs in the original review or updates in 20011 and 2012. Cure or improvement have been described in high quality observational studies: (1) A single study describes spontaneous improvement of meralgia paraesthetica in 20 (69%) of 29 cases. (2) Four studies evaluating the injection of corticosteroid and local anaesthetic found cure or improvement in 130 (83%) out of a combined total of 157 cases. (3) Surgical treatments have been found to be beneficial in 264 (88%) out of 300 cases treated with decompression (nine studies); and 45 (94%) out of 48 cases treated with neurectomy (three studies). (4) Ninety-nine (97%) out of 102 patients with iatrogenic meralgia paraesthetica recovered completely (three studies).

AUTHORS' CONCLUSIONS

In the absence of any published RCTs or quasi-RCTs, the objective evidence base for treatment choices in meralgia paraesthetica is weak. High quality observational studies report comparable high improvement rates for meralgia paraesthetica following local injection of corticosteroid and surgical interventions (either nerve decompression or neurectomy). However, a similar outcome has been reported without any intervention in a single natural history study.

[Experimental study on three repairing methods for femoral nerve injury after ligation in rats]

OBJECTIVE

To investigate the effects of 3 methods (suture removal, suture removal with epineurium neurolysis, and ligated femoral nerve resection with end-end suture) in repairing femoral nerve injury after ligation in different periods so as to provide a reference for clinical use of repairing iatrogenic ligation injury of the peripheral nerve.

METHODS

A total of 120 adult female Sprague Dawley rats, weighing (200 +/- 20) g, were used to prepare the animal models of left femoral nerve ligation, and were divided into groups A (n=40), B (n=40), and C (n=40) according different repairing methods. At immediate, 1, 3, and 5 months (10 rats each time point) after ligation, suture removal was performed in group A, suture removal with epineurium neurolysis in group B, and ligated femoral nerve resection with end-end suture in group C. At 3 months after operation, the foot-base angle (FBA) and the heels-tail angle (HTA), action potential and conduction velocity of femoral nerve, and wet weight of quadriceps femoris muscle (QFM) were measured; the samples of quadriceps femoris and femoral nerve were harvested for histological observation, muscle fiber count, and nerve fiber passing rate measuring.

RESULTS

The FBA in group A was significant smaller than that in group C at immediate, 1, 3, and 5 months (P < 0.05), but there was no significant difference between groups A and B (P > 0.05). The HTA in group A was significantly smaller than that in group C at immediate, 1, 3, and 5 months (P < 0.05), and the THA in group B was significantly smaller than that in group C at 1, 3, and 5 months (P < 0.05). The wet weight of QFM in group B was significantly higher than that in group C at immediate, 3, and 5 months (P < 0.05), and the wet weight of QFM in group A was significantly higher than that in group C at immediate and 3 months (P < 0.05), but no significant difference was found between groups A and B at immediate, 1, and 3 months (P > 0.05). There was significant difference in the action potential of femoral nerve between group A and groups B and C at immediate and 1 month (P < 0.05), but there was no significant difference between other groups at 3 and 5 months (P > 0.05) except between groups A and C at 5 months (P < 0.05). The conduction velocity of femoral nerve in group A was significantly faster than that in group C at immediate, 1, and 5 months (P < 0.05), and it was significantly faster in group A than in group B at immediate and 1 month (P < 0.05), but no significant difference was found between groups A and B at 3 and 5 months (P > 0.05), between groups B and C at other time points (P > 0.05) except at immediate (P < 0.05). The count of muscle fibre of the quadriceps femoris was significantly more in groups A and B than in group C at immediate (P < 0.05); it was significantly more in group A than in group B at 5 months (P < 0.05). The passing rate of the femoral nerve fiber was significantly higher in group A than in groups B and C at 3 months (P < 0.05), but no significant difference was found between the other groups (P > 0.05).

CONCLUSION

After femoral nerve ligation, suture removal method has the best effect at early term, the next is epineurium neurolysis method, and the worst is the ligation femoral nerve resection with end-end suture repair.

Infrapatellar branch of saphenous neurectomy for painful neuroma: a case report

We present the case of an 18-year-old woman who was healthy other than a history of multiple arthroscopic right knee surgeries culminating in subtotal lateral meniscectomy in a valgus knee. The patient was referred to our office for evaluation for realignment osteotomy and meniscal transplantation. Her diagnosed case of neuroma of the infrapatellar branch of the saphenous nerve was managed with neurectomy, which produced prompt and complete resolution of pain.

Venous graft-derived cells participate in peripheral nerve regeneration

BACKGROUND

Based on growing evidence that some adult multipotent cells necessary for tissue regeneration reside in the walls of blood vessels and the clinical success of vein wrapping for functional repair of nerve damage, we hypothesized that the repair of nerves via vein wrapping is mediated by cells migrating from the implanted venous grafts into the nerve bundle.

METHODOLOGY/PRINCIPAL FINDINGS

To test the hypothesis, severed femoral nerves of rats were grafted with venous grafts from animals of the opposite sex. Nerve regeneration was impaired when decellularized or irradiated venous grafts were used in comparison to untreated grafts, supporting the involvement of venous graft-derived cells in peripheral nerve repair. Donor cells bearing Y chromosomes integrated into the area of the host injured nerve and participated in remyelination and nerve regeneration. The regenerated nerve exhibited proper axonal myelination, and expressed neuronal and glial cell markers.

CONCLUSIONS/SIGNIFICANCE

These novel findings identify the mechanism by which vein wrapping promotes nerve regeneration.

A short postgraduate anatomy course may improve the junior surgical residents' anatomy knowledge for the nerves of the inguinal region

BACKGROUND AND AIM

Inguinal hernia repair is one of the most common operations in a junior surgical resident's postgraduate training. Short recall courses can improve junior residents' anatomy knowledge and results in better surgical outcomes. We aimed to investigate the effect of a short course on anatomical competency during inguinal hernia repairs.

METHODS

During the first 25 inguinal hernia repairs, two junior residents were asked to identify iliohypogastric, ilioinguinal, and genital branch of genitofemoral nerves. Then, the residents were given a short recall course by anatomists. Afterwards, the participants were taken into an in-vivo anatomy test again. The same parameters were recorded in another 25 inguinal hernia repairs. In addition to the nerve identification records, case characteristics [body mass index (BMI < or = 25 vs. >25), hernia type (indirect vs. direct), and anesthesia used (general or regional vs. local)] were recorded.

RESULTS

Anatomy education had a clear impact on the correct identification rates for the iliohypogastric and ilioinguinal nerves. The rates increased from 70% to 90% and above. Correct identification rate for the three nerves together significantly increased from 16 to 52% following anatomy education (P = 0.006). All three nerves were identified with significantly higher success rates after anatomy education. The increase in the success rate for identification of the genital branch of genitofemoral nerve was 4-fold.

CONCLUSIONS

Short anatomy courses in specific subjects for junior surgical residents given by formal anatomists may be effective during postgraduate education. The benefit obtained in the present study for the inguinal region nerves may be expanded to more important anatomical structures, such as the recurrent laryngeal nerve in a thyroidectomy, or more complex subjects.

The course of the distal saphenous nerve: a cadaveric investigation and clinical implications

INTRODUCTION

Injury to the saphenous nerve at the ankle has been described as a complication resulting from incision and dissection over the distal tibia and medial malleolus. However, the exact course and location of the distal saphenous nerve is not well described in the literature. The purpose of this study was to determine the distal limit of the saphenous nerve and its anatomic relationship to commonly identified orthopaedic landmarks and surgical incisions.

METHODS

Sixteen cadaveric ankles were examined at the level of the distal tibia medial malleolus. An incision was made along the medial aspect of the lower extremity from the knee to the hallux to follow the course and branches of the saphenous nerve under direct visualization. We recorded the shortest distance from the most distal visualized portion of the saphenous nerve to the tip of the medial malleolus, to the antero-medial arthroscopic portal site, and to the tibialis anterior tendon.

RESULTS

The saphenous nerve runs posterior to the greater saphenous vein in the leg and divides into an anterior and posterior branch approximately 3 cm proximal to the tip of the medial malleolus. These branches terminate in the integument proximal to the tip of the medial malleolus, while the vein continues into the foot. The anterior branch ends at the anterior aspect of the medial malleolus near the posterior edge of the greater saphenous vein. The posterior branch ends near the posterior aspect of the medial malleolus. The average distance from the distal-most visualized aspect of the saphenous nerve to the tip of the medial malleolus measured 8mm +/-; 5mm; from the nerve to the medial arthroscopic portal measured 14mm +/-2mm; and from the nerve to the tibialis anterior measured 16mm +/-3mm. In only one case (of 16) was there an identifiable branch of the saphenous nerve extending to the foot and in this specimen it extended to the first metatarsophalangeal joint. The first metatarsophalangeal joint was innervated by the superficial peroneal nerve in all cases. Small variations were also noted.

DISCUSSION AND CONCLUSIONS

This study highlights the proximity of the distal saphenous nerve to common landmarks in orthopaedic surgery. This has important clinical implications in ankle arthroscopy, tarsal tunnel syndrome, fixation of distal tibia medial malleolar fractures, and other procedures centered about the medial malleolus. While the distal course of the saphenous nerve is generally predictable, variations exist and thus the orthopaedic surgeon must operate cautiously to prevent iatrogenic injury. To avoid saphenous nerve injury, incisions should stay distal to the tip of the medial malleolus. The medial arthroscopic portal should be more than one centimeter from the anterior aspect of the medial malleolus which will also avoid the greater saphenous vein. Incision over the anterior tibialis tendon should stay within one centimeter of the medial edge of the tendon.

[Clinical application of the reverse neurocutaneous flap with anterior cutaneous branch of the femoral nerve supplied by the perforator of saphenous artery]

OBJECTIVE

To report the operative technique and clinical application of the neurocutaneous flap with anterior cutaneous branch of the femoral nerve supplied by the perforator of saphenous artery.

METHODS

The reverse neurocutaneous flap with anterior cutaneous branch of the femoral nerve supplied by the perforator of saphenous artery was used for repairing the defect around knee or at the upper pad of leg. Since Oct. 2005, 16 cases were treated. The flap size ranged from 15 cm x 7 cm to 30 cm x 15 cm. Flap rotation angle ranged from l00 degrees to 180 degrees.

RESULTS

13 flaps survived completely. Flap necrosis happened at the 1/7 - 1/5 distal end of the 3 flaps, which healed with dressing or local flap advancement. The patients were followed up for 6 to 24 months with satisfactory functional and cosmetic results. There was no morbidity at the donor site.

CONCLUSION

The flap has the advantages of both the perforator flap and the neurocutaneous flap. The size of the neurocutaneous flap with the anterior cutaneous branch of the femoral nerve can be enlarged for the large defect at lower extremity.

Sonographic assessment of the lateral femoral cutaneous nerve

PURPOSE

To evaluate the ability of high-frequency sonography to evaluate the lateral femoral cutaneous nerve (LFCN).

METHODS

A cadaveric study was performed on 5 cadavers to outline the normal course of the LFCN. Next, 37 LFCNs in 21 volunteers were evaluated via sonography with a 5-13-MHz linear-array transducer.

RESULTS

The LFCN was easily identified in our dissections. It always entered the thigh under the inguinal ligament and coursed superficially to the sartorius muscle. In 2/10 (20%) cases, anatomical variants were observed. Sonography revealed the LFCN in 26/37 (70%) cases. The relationships of the nerve with the deep circumflex iliac artery, the anterior superior iliac spine, and the sartorius were visualized. Neuromas were observed bilaterally in 1 volunteer.

CONCLUSION

The LFCN can be seen in the groin with the aid of sonography.

Treatment for meralgia paraesthetica

BACKGROUND

Meralgia paraesthetica is a clinical syndrome for which a number of treatments are in common use, including conservative measures, injection of corticosteroid with local anaesthetic and surgery. We aimed to examine the evidence for the relative efficacy of these interventions.

OBJECTIVES

To assess the relative efficacy of commonly used treatments.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Trials Register (April 2008), MEDLINE (January 1 1966 to April 18 2008), EMBASE (January 1 1980 to May 12 2008) and CINAHL (January 1 1980 to May 12 2008) for randomised controlled studies. Non-randomised studies were identified by searching MEDLINE (January 1 1966 to April 18 2008) and EMBASE (January 1 1980 to May 12 2008). We also inspected the reference lists of these studies to identify further studies.

SELECTION CRITERIA

We were unable to identify any randomised controlled or quasi-randomised controlled trials. We therefore looked for high quality observational studies meeting the following criteria:(1) At least five cases of meralgia paraesthetica.(2) Follow-up of at least three months after intervention (if any).(3) At least 80% of cases followed up.

DATA COLLECTION AND ANALYSIS

Relevant data from each study meeting the selection criteria were extracted independently by all three authors and transferred into a data extraction form created for the review.

MAIN RESULTS

We found no randomised controlled or quasi-controlled trials. Cure or improvement have been described in high quality observational studies:(1) A single study describes spontaneous improvement of meralgia paraesthetica in 20 (69%) out of 29 cases.(2) Four studies evaluating the injection of corticosteroid and local anaesthetic found cure or improvement in 130 (83%) out of a combined total of 157 cases.(3) Surgical treatments have been found to be beneficial in 264 (88%) out of 300 cases treated with decompression (nine studies); and 45 (94%) out of 48 cases treated with neurectomy (three studies).(4) Ninety-nine (97%) out of 102 patients with iatrogenic meralgia paraesthetica recovered completely (three studies).

AUTHORS' CONCLUSIONS

In the absence of any published randomised controlled or quasi-randomised controlled trials, the objective evidence base for treatment choices in meralgia paraesthetica is weak. High quality observational studies report comparable high improvement rates for meralgia paraesthetica following local injection of corticosteroid and surgical interventions (either nerve decompression or neurectomy). However, a similar outcome has been reported without any intervention in a single natural history study.

Involvement of the lateral femoral cutaneous nerve as source of persistent pain after total hip arthroplasty

This report describes a situation in which the lateral femoral cutaneous (LFC) nerve was the source of incisional pain in a patient after a total hip arthroplasty. The painful scar was denervated by an approach that resected just the posterior branch of the LFC nerve. This was done through an incision near the anterior superior iliac crest, avoiding any potential exposure of the implant. One of the 3 patients reported here had a coexisting meralgia paresthetica that was treated by the same operative approach. The orthopedic surgeon should include the LFC nerve as an origin of persistent pain after total hip arthroplasty.

Neurotization improves contractile forces of tissue-engineered skeletal muscle

Engineered functional skeletal muscle would be beneficial in reconstructive surgery. Our previous work successfully generated 3-dimensional vascularized skeletal muscle in vivo. Because neural signals direct muscle maturation, we hypothesized that neurotization of these constructs would increase their contractile force. Additionally, should neuromuscular junctions (NMJs) develop, indirect stimulation (via the nerve) would be possible, allowing for directed control. Rat myoblasts were cultured, suspended in fibrin gel, and implanted within silicone chambers around the femoral vessels and transected femoral nerve of syngeneic rats for 4 weeks. Neurotized constructs generated contractile forces 5 times as high as the non-neurotized controls. Indirect stimulation via the nerve elicited contractions of neurotized constructs. Curare administration ceased contraction in these constructs, providing physiologic evidence of NMJ formation. Histology demonstrated intact muscle fibers, and immunostaining positively identified NMJs. These results indicate that neurotization of engineered skeletal muscle significantly increases force generation and causes NMJs to develop, allowing indirect muscle stimulation.

Modified anterior compartment resection of the thigh

For large soft tissue sarcomas of the anterior thigh, an anterior compartment resection is often performed. This may leave the patient with the inability to extend the knee. In our practice, we find that it is usually possible to preserve one of the heads of the quadriceps, usually the vastus medialis, with intact innervation, and thus preserve significant extension function of the knee joint, while the requirements for a radical oncologic procedure are being met. The modified anterior compartment resection preserves one or more heads of the quadriceps and requires a thorough knowledge of the course and distribution of the branches of the femoral nerve from the level of the inguinal ligament to their termination at the individual heads of the quadriceps femoris.

Ultrasound examination in the surgical treatment of lower extremity peripheral nerve injuries: part II

OBJECTIVE

The aim of this clinical study was to evaluate the benefits of ultrasonographic imaging in the surgical treatment of lower extremity peripheral nerve lesions.

METHODS

Peripheral nerves in the lower extremity were evaluated by using real-time ultrasonographic examination. The capability of ultrasonography in terms of determination the type of injury, the position of the proximal and distal nerve stumps, the presence or absence of a neuroma, and perilesional scar tissue were evaluated.

RESULTS

Twenty-two cases with lower extremity peripheral nerve injuries aged between 21-52 years old were included in this study. Five (23%) had femoral nerve injuries and 17 (77%) sciatic nerve injuries. A total nerve transsection was diagnosed in 1 (5%) case while the remaining 21 (95%) cases had incomplete sectioning of the nerves.

CONCLUSION

Preoperative and intraoperative ultrasonography for lower extremity peripheral nerve lesions may be used in the description of the degree of injury, determination of complete or incomplete nerve sectioning, the presence of hematoma and foreign body, the continuity of the nerve, determination of nerve stumps, perilesional scar tissue, and the presence of neuroma.

Effects of intermittent lower limb ischaemia on coronary blood flow and coronary resistance in pigs

AIM

Intermittent limb ischaemia prior to cardiac ischaemia is a cardioprotective stimulus. This study was to investigate whether this peripheral stimulus had any effects on basal coronary blood flow and resistance, and to explore its potential mechanisms by studying the effect of femoral nerve transection and Katp blockade by glibenclamide.

METHODS

Remote ischaemic preconditioning (rIPC) was induced by four 5-min cycles of lower limb ischaemia. Coronary resistance was measured using standard formulae and coronary blood flow in the left anterior descending artery (LAD) by a flow probe. In experiment 1, coronary ischaemia was induced by inflation of a cuff placed around the mid-LAD, and inflated until cessation of flow. Left ventricular (LV) function was assessed using dp/dt and Tau at 1 and 30 min of ischaemia. Experiment 1: 20 pigs were randomized to control (n = 6), rIPC (n = 7) or femoral nerve transection + rIPC (n = 7) groups. The femoral nerve was transected before the rIPC protocol. All data were collected at fixed heart rates of 120 bpm. Coronary resistance was decreased and flow was increased significantly by the rIPC stimulus (P = 0.003, P = 0.016, paired t-test), and these changes were preserved after femoral nerve transection. Experiment 2: 19 pigs were randomized to control (n = 5), rIPC (n = 8) or glibenclamide-treated rIPC (n = 6) groups. Data were collected at baseline, and during incremental pacing between 120 and 180 bpm.

RESULTS

Experiment 1: Coronary resistance was decreased and flow was increased significantly by rIPC stimulus (P = 0.003, P = 0.016, paired t-test), and these changes were preserved after femoral nerve transaction. rIPC was associated with superior LV function (dp/dt(max)) at 30 min, compared with controls and the rIPC + femoral nerve transaction group. Experiment 2: Coronary resistance was significantly lower, and LAD flow was significantly higher in rIPC group (P < 0.0001, P = 0.0008, two-way anova). These effects were reversed in the glibenclamide group.

CONCLUSION

The rIPC stimulus leads to reduced coronary resistance and increased flow. This effect, while modified by glibenclamide appears to be a generic effect of remote ischaemia rather than a direct preconditioning effect.

[The infragluteal perforator flap]

PURPOSE

Pressure sores of the ischial tuberosities are mostly covered with fascio- or myocutaneous flaps of the posterior thigh. In doing so, vascular territories of adjacent flaps are violated, which are not available any more in case of ulcer recurrences. In consideration of the high recurrence rates of pressure sores in paraplegics, we developed an infragluteal perforator flap that spares adjacent vascular territories.

PATIENTS/MATERIAL AND METHOD

Infragluteal perforator flaps were dissected in five fresh human cadavers to investigate the anatomic relations of the cutaneous branches of the inferior gluteal artery and the inferior clunial nerves and to define the anatomic landmarks for clinical application of an innervated flap. In six paraplegic patients with primary (5/6) and secondary (1/6) pressure sores of the ischial tuberosity, infragluteal perforator flaps were used for wound coverage. The donor defect was closed primarily and postoperative care and patient mobilisation followed a standardised protocol.

RESULTS

In eleven infragluteal perforator flaps that were dissected in cadavers and patients, we found one or two cutaneous branches of the descending branch of the inferior gluteal artery at the lower border of the gluteus maximus muscle that supplied the infragluteal skin. Infragluteal perforator flaps could be harvested on these perforator vessels and transferred to the ischial defects without tension due to the excellent mobility of the skin island. The descending branch of the inferior gluteal artery could be spared in all cases for future flaps. In one patient with multiple recurrences of an ischial pressure sore flap necrosis occurred due to venous congestion. The other five infragluteal perforator flaps healed without complications.

CONCLUSION

The infragluteal perforator flap is suitable for the closure of pressure sores of the ischial tuberosities and can be used as a sensitised flap by inclusion of the inferior clunial nerves. Compared to traditional pedicled flaps of the posterior thigh, the infragluteal perforator flap reduces donor site morbidity and spares the vascular territories of adjacent flaps for future recurrent ulcers.

Effects of Thermal Stimulation, Applied to the Hindpaw via a Hot Water Bath, upon Ovarian Blood Flow in Anesthetized Nonpregnant Rats

The effects of thermal stimulation, applied to the hindpaw via a hot bath set to either 40 degrees C (non-noxious) or 49 degrees C (noxious), upon ovarian blood flow were examined in nonpregnant anesthetized rats. Ovarian blood flow was measured using a laser Doppler flowmeter. Blood pressure was markedly increased following 49 degrees C stimulation. Ovarian blood flow, however, showed no obvious change during stimulation, although a small increase was observed after stimulation. Ovarian blood flow and blood pressure responses to 49 degrees C stimulation were abolished after hindlimb somatic nerves proximal to the stimuli were cut. Heat stimulation (49 degrees C) resulted in remarkable increases in both ovarian blood flow and blood pressure in rats in which the sympathetic nerves supplying the ovary were cut but the hindlimb somatic nerves remained intact. The efferent activity of the ovarian plexus nerve was increased during stimulation at 49 degrees C. Stimulation at 40 degrees C had no effect upon ovarian blood flow, blood pressure or ovarian plexus nerve activity. Electrical stimulation of the distal part of the severed ovarian plexus nerve resulted in a decrease in both the diameter of ovarian arterioles, observed using a digital video microscope, and ovarian blood flow.The present results demonstrate that noxious heat, but not non-noxious warm, stimulation of the hindpaw skin in anesthetized rats influences ovarian blood flow in a manner that is attributed to reflex responses in ovarian sympathetic nerve activity and blood pressure.

The role of osteopontin in tendon tissue remodeling after denervation-induced mechanical stress deprivation

It has been shown that musculoskeletal tissues undergo dynamic tissue remodeling by a process that is quite sensitive to the mechanical environment. However, the detailed molecular mechanism underlying this process remains unclear. We demonstrate here that after denervation-induced mechanical stress deprivation, tendons undergo dynamic tissue remodeling as evidenced by a significant reduction of the collagen fibril diameter. Importantly, the transient up-regulation of osteopontin (OPN) expression was characteristic during the early phase of tendon tissue remodeling. Following this dynamic change of OPN expression, matrix metalloproteinase (MMP)-13 expression was induced, which presumably accounts for the morphological changes of tendon by degrading tendon collagen fibrils. The modulation of MMP-13 expression by OPN was specific, since the expression of MMP-2, which is also known to be involved in tissue remodeling, did not alter in the tendons under the absence or presence of OPN. We also demonstrate that the modulation of MMP-13 expression by OPN is due to the signaling through cell surface receptors for OPN. Thus, we conclude that OPN plays a crucial role in conveying the effect of denervation-induced mechanical stress deprivation to the tendon fibroblasts to degrade the extracellular matrices by regulating MMP-13 expression in tendon fibroblasts.

Neuroregeneration in Composite Tissue Allografts: Effect of Low-Dose FK506 and Mycophenolate Mofetil Immunotherapy

BACKGROUND

The immunosuppressant FK506 has been reported to increase the rate of peripheral nerve regeneration in nerve crush injury and nerve allograft models. The purpose of this study was to determine whether low doses of FK506 and mycophenolate mofetil had a neuroregenerative effect in revascularized peripheral nerve allografts in a rat hind limb transplantation model.

METHODS

Wistar Furth rat recipients received limbs from syngeneic Wistar Furth donors (group 1, n = 4) or from allogeneic August X Copenhagen Irish rat donors (group 2, n = 6). Wistar Furth recipients received limbs from August X Copenhagen Irish donors and were treated with FK506/mycophenolate mofetil for 5 months (group 3, n = 7). At the end of the follow-up period, histomorphometric analysis of sciatic and tibial nerves from transplanted and intact hind limbs was conducted. Sciatic and tibial nerves were examined at the level of coaptation and near the neuromuscular junction, respectively.

RESULTS

Transplanted limbs in groups 1 and 3 completed the study without rejection, while the limbs in group 2 were rejected within a few days. Sciatic and tibial nerve analysis in groups 1 and 3 limbs showed myelinated axons of various diameters but in significantly fewer numbers than in nontransplanted contralateral nerves. The number and size of myelinated axons of transplanted nerves at corresponding levels were not significantly different between syngeneic and allogeneic (FK506/mycophenolate mofetil-treated) transplants.

CONCLUSIONS

The authors conclude that long-term neuroregeneration of revascularized peripheral nerves using low-dose FK506/mycophenolate mofetil was similar to that of syngeneic transplants. The occurrence of acute rejection episodes with low-dose FK506/mycophenolate mofetil did not appear to benefit nor impair neuroregeneration.

[A case of retroperitoneal schwannoma extracted by a nerve sparing procedure under microscopic surgery]

We report a case in which we extracted retroperitoneal schwannoma by a nerve sparing procedure under microscopic surgery. A 63-year-old male was diagnosed with left ureter stone and left hydronephrosis. A left retroperitoneal tumor was found by the abdominal ultrasound sonography. Abdominal computed tomography and magnetic resonance imaging revealed the mass 20 mm in diameter in the retroperitoneal cavity. We considered that the tumor arose from the left femoral nerve, and removed it under microscopic surgery. There was no malignancy. There was neither recurrence nor neuropathy after operation. Since it is rare to find the origin nerve of schwannoma before operation, we report our experience.

Denervation alters mRNA levels of repair-associated genes in a rabbit medial collateral ligament injury model

Previous experiments revealed that denervation impairs healing of the MCL. This suggested the hypothesis that denervation would decrease repair-associated mRNA levels in the injured MCL when compared with normally innervated injured MCL. Adult, skeletally mature female rabbits were assigned to one of four groups: unoperated control, femoral nerve transection alone (denervated controls), MCL partial tear or denervated MCL partial tear. At three days, two weeks, six weeks or sixteen weeks post-surgery, cohorts of 6 rabbits from each experimental group were killed. Ligaments were harvested, RNA extracted and RT-PCR was performed using rabbitspecific primers. In the denervated injury group, mRNA levels for the angiogenesis-associated gene MMP-13, matrix components Collagen I and III, growth factor TGF-beta and angiogenesis inhibitors TIMP-3, and TSP-1 had all increased by two-weeks post-injury, in comparison to the non-denervated injury group (p < or = 0.01). An increased level of TSP-1 mRNA was also detected in the denervated injured group at sixteen weeks post injury (p < or = 0.01). Contrary to the initial hypothesis, denervation led to increased mRNA levels for many relevant molecules during the early stages of MCL healing. Thus, inappropriate timing of over-expression of some molecules may potentially contribute to the decreased quality of the scar tissue, particularly molecules such as TSP-1. Neuronal derived factors strongly influence the in vivo metabolic activity of ligament and scar fibroblasts in the initial phases of healing.

Femoral neuropathy in a dog with iliopsoas muscle injury

OBJECTIVE

To report femoral nerve dysfunction caused by focal iliopsoas muscle injury and treated by performing tenectomy of the muscle insertion.

STUDY DESIGN

Case report.

ANIMALS

A 4-year-old, castrated male, English Mastiff.

RESULTS

Iliopsoas muscle injury caused femoral nerve deficits and severe pain. Focal injury was not detected by ultrasonography or computed tomography but was visible on magnetic resonance (MRI) images. Tenectomy of the insertion of the iliopsoas muscle relieved signs of pain.

CONCLUSIONS

Femoral nerve dysfunction may occur with iliopsoas muscle injury.

CLINICAL RELEVANCE

Iliopsoas muscle injury should be considered in patients with hip pain and MRI is a useful test for diagnosis. Tenectomy may be indicated for relief of chronic iliopsoas muscle pain.

Intraoperative somatosensory evoked potentials to facilitate peripheral nerve release

PURPOSE

The significance of intraoperative somatosensory evoked potentials (SSEP) monitoring is well known during spinal surgery. This technology could be beneficial during peripheral nerve surgery as well. In order to illustrate potential applications, two cases of successful peripheral nerve release demonstrated by on-line, intraoperative, SSEP are reported. Clinical and technical features: The first case presents a complex brachial plexus lesion involving two mixed sensory-motor nerves: median and ulnar. The second case involved an entrapment neuropathy of the lateral femoral cutaneous nerve, a pure sensory nerve (meralgia paresthetica). For each patient we elicited specific peripheral nerve SSEP (recorded using bipolar cephalic montage) by stimulating each nerve independently. In each case, during difficult nerve dissection and after having excluded other possible factors of intraoperative SSEP variations, an increase of the SSEP amplitude was observed, and later correlated with favourable patient clinical outcome.

CONCLUSIONS

Two cases demonstrate that intraoperative SSEP monitoring may provide an effective tool to guide surgical dissection during peripheral nerve release. This technique has potentially beneficial clinical applications and warrants further investigation.