The Anatomic Relationship of the Sciatic Nerve to the Lesser Trochanter: Implications for Anterior Sciatic Nerve Block

Arthroscopic Lesser Trochanter Osteoplasty, Quadratus Femoris Debridement, and Sciatic Neurolysis via Posterior Approach for Ischiofemoral Impingement

Ischiofemoral impingement (IFI) syndrome is considered the narrowing of the ischiofemoral space (IFS), leading to pathological changes in the quadratus femoris and sciatic nerve, causing posterior hip and sciatica-like pain. Open or arthroscopic resection of the lesser trochanter to enlarge the IFS is the main surgical procedure. However, there is a lack of research on isolated IFI, and currently known surgical procedures are at risk of weakening the flexion strength of the hip joint. In this study, four patients, who were diagnosed with isolated IFI and had undergone arthroscopic treatment with partial resection of the lesser trochanter, debridement of the quadratus femoris, and decompression of the sciatic nerve, were reviewed. To the best of our knowledge, this is the first study to describe the management of IFI using a series of surgical procedures via a posterior approach as an effective treatment option. The outcomes of this study broadened the strategies for IFI management.

Course of the sciatic nerve on magnetic resonance imaging in patients with osteoarthritis of the hip

BACKGROUND

Sciatic nerve palsy is a serious complication after total hip arthroplasty (THA). This is the first study to report the relationship between the sciatic nerve and the acetabulum on magnetic resonance imaging (MRI) before THA.

METHODS

235 patients underwent 261 elective, primary THAs via the mini-incision posterolateral approach. We measured the horizontal distance (mm) and vertical distance (mm) from the posterior edge of the acetabulum to the sciatic nerve by T1-weighted imaging on an axial section of the centre of the femoral head. We defined the Dysplastic Group as having a posterior acetabular sector angle (PASA) <90° and the Non-dysplastic Group as having a PASA ⩾ 90°. We compared anatomical distances and angles between the 2 groups.

RESULTS

The horizontal and vertical distances were (mean ± SD) 8.0 ± 9.2 mm and 14 ± 5.0 mm from the posterior edge of the acetabulum to the lateral edge of the sciatic nerve, respectively. The acetabular anteversion (AA), anterior acetabular sector angle (AASA), and PASA were (mean ± SD) 19 ± 6.7°, 49 ± 8.4°, and 87 ± 8.6°, respectively. The horizontal and vertical distances were positively correlated (p < 0.0001). AA and PASA were positively correlated with the horizontal distances (p < 0.0001) as well as with the vertical distances (p = 0.0017 and p = 0.0438, respectively). The horizontal and vertical distances were significantly shorter in the Dysplastic Group than in the Non-dysplastic Group (p < 0.0001 and p = 0.021, respectively).

CONCLUSIONS

In cases of posterior acetabular dysplasia we have to be mindful of the course of the sciatic nerve.

Treatment strategies for ischiofemoral impingement: a systematic review

PURPOSE

There has been relatively little information about the treatment for ischiofemoral impingement (IFI) because of its rarity as well as the uncertainty of diagnosis. The aim of this study was to provide the reader with the available treatment strategies and their related outcomes for IFI based on the best available evidence, whilst highlighting classically accepted ways of treatment as well as relatively new surgical and non-surgical techniques.

METHODS

A systematic review of the literature from Medline, Embase, AMED, Cochrane and Google Scholar was undertaken since inception to December 2017 following the PRISMA guidelines. Clinical outcome studies, prospective/retrospective case series and case reports that described the treatment outcome for IFI were included. Animal or cadaveric studies, trial protocols, diagnostic studies without any description of treatments, technical notes without any results, and review articles were excluded.

RESULTS

This systematic review found 17 relevant papers. No comparative studies were included in the final records for qualitative assessment, which means all the studies were case series and case reports. Eight studies (47.1%) utilised non-surgical treatment including injection and prolotherapy, followed by endoscopic surgery (5 studies, 29.4%) then open surgery (4 studies, 23.5%). Mean age of the participants was 41 years (11-72 years). The mean follow-up was 8.4 months distributed from 2 weeks to 2.3 years. No complications or adverse effects were found from the systematic review.

CONCLUSION

Several treatment strategies have been reported for IFI, and most of them have good short- to medium-term outcomes with a low rate of complications. However, there are no comparative studies to assess the superiority of one technique over another, thus further research with randomised controlled trials is required in this arena. This study explores the wide variety and categories of different treatments used for IFI to guide physicians and shed light on what can be done for this challenging cohort of patients.

LEVEL OF EVIDENCE

III.

Endoscopic Lesser Trochanter Resection With Refixation of the Iliopsoas Tendon for Treatment of Ischiofemoral Impingement

Ischiofemoral impingement is a source of hip pain derived from impingement between the lesser trochanter and the ischium. Lesser trochanter excision has been recommended for recalcitrant ischiofemoral impingement through either an anterior or posterior approach. However, neither of these approaches involves refixation of the iliopsoas tendon. We describe an endoscopic procedure involving anterior trochanter-plasty, minimizing the risk of sciatic complications, with refixation of the partially detached iliopsoas tendinous insertion, potentially minimizing compromise to hip flexion strength and anterior hip stability.

Endoscopic lesser trochanter resection for treatment of ischiofemoral impingement

Ischiofemoral impingement (IFI) is an uncommon source of hip pain characterized by abnormal proximity of the lesser trochanter (LT) and the anterior border of ischium. The condition can be treated non-operatively but in severe cases, LT excision can provide beneficial results. Most previous descriptions for IFI operation use an open surgical approach but with the advancement of arthroscopic surgery, the LT can be approached less invasively. This study describes a simple endoscopic method to decompress the LT. Due to the posteromedial location of LT, this method requires careful positioning of the leg, and the use of curved type instruments is recommended. Also, it is helpful to assess the amount of resection with a properly oriented fluoroscopic view.

Ultrasound-guided medial mid-thigh approach to sciatic nerve block with a patient in a supine position

We report the use of a ‘medial mid-thigh approach (medial approach),’ a new approach for performing ultrasound-guided sciatic nerve blockade (SNB) with patients in a supine position. Fifty-four patients undergoing knee surgery under general anesthesia and a combined femoral nerve block (FNB) and SNB were included in the study. After FNB, an ultrasound-guided medial approach was used to perform the SNB. The patient was placed in a supine position, and the hip and knee joints were flexed with the leg rotating externally. A linear ultrasound transducer was positioned perpendicular to the skin at the level of the upper mid-thigh. The sciatic nerve was identified in all patients using ultrasound imaging, and the distance to the nerve was 3.0–5.5 cm. A combined ultrasound- and nerve stimulator-guided SNB was then performed, and 0.375% ropivacaine was administered. The block was successful in all patients, and the mean duration of the sensory and motor blockade was 11.9 and 8.2 h, respectively. In this study, the medial approach was highly successful and easy to perform. As performing a simultaneous FNB and SNB with patients in a supine position has several potential advantages, future studies should compare this approach with other more proximal approaches for performing SNB.

[Peripheral nerve blocks of the lower extremities. Clinical and practical aspects]

Peripheral nerve blocks (PNBs) of the lower extremities are effective techniques for anesthesia and postoperative pain control. So far, these techniques have been used less frequently than PNBs of the upper limb. Nevertheless, growing awareness of complications of neuroaxial techniques, improved equipment and modern techniques for nerve localization have led to an increased use of PNBs of the lower limb. Anesthesiologists should be familiar with the anatomical basics and procedural details of these PNBs. They should also know the typical complications and side-effects and thoroughly inform patients about such potential problems. Continuous PNBs (perineural catheters) allow the benefits of PNBs to be prolonged into the postoperative period. Compared to continuous neuroaxial techniques continuous PNBs are equally effective for pain control but seem to be associated with fewer complications and side-effects.

The anterior combined approach via a single skin injection site allows lower limb anesthesia in supine patients

PURPOSE

Lower limb anesthesia (LLA) requires the combination of, at least, three-in-one and sciatic nerve (SCN) blocks. Anterior approaches are easier to perform with minimal discomfort in supine patients, specially for traumatology. Feasibility of a single needle entry combined approach is reported.

CLINICAL FEATURES

The combined landmark was applied in 119 ASA I and II patients (32-68 yr) scheduled for surgery below the knee. Needle (nerve stimulation applied through a single 150-mm long b-bevelled insulated needle) was inserted at the midpoint between the two classical approaches. Thirty and 15 mL of 0.5% ropivacaine were injected close to the femoral and the SCN, respectively. During the following 45 min, the extent of sensory block and knee and ankle motor block were assessed. Landmarks were determined within 1.7 min (0.7-2.2 min). The entire procedure was performed within 4.2 min (2.9-7.1 min) from the determination of the landmark to the SCN infiltration. The three-in-one technique was successful in 89.9% while SCN was successful in 94.9%. Femoral and tibial nerves were always blocked. Blockade of the posterior cutaneous femoral nerve was observed in 78% of patients. The extent and the quality of the sensory block always allowed surgery. Additional iv sedation was needed in 32.6% of patients. Motor block (adapted Bromage's scale > 2) was observed in the femoral (98.3%), the obturator (84.8%), the tibial (97.4%) and the common peroneal (85.7%) nerve distributions. No important adverse effects were recorded.

CONCLUSION

The anterior combined approach via a single needle entry represents a technically easy and reliable technique to perform LLA in the supine patient.