Superficial peroneal nerve anatomic variability changes surgical technique

The Association between Anatomical Variants of Musculoskeletal Structures and Nerve Compressions of the Lower Limb: A Systematic Review and Meta-Analysis

Objective: The aim of this study was to describe the main anatomical variants and morphofunctional alterations in the lower limb that compress surrounding nervous structures in the gluteal region, thigh region, and leg and foot region. Methods: We searched the Medline, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS databases from their inception up to October 2023. An assurance tool for anatomical studies (AQUA) was used to evaluate methodological quality, and the Joanna Briggs Institute assessment tool for case reports was also used. Forest plots were generated to assess the prevalence of variants of the gluteal region, thigh, and leg. Results: According to the forest plot of the gluteal region, the prevalence was 0.18 (0.14-0.23), with a heterogeneity of 93.52%. For the thigh region, the forest plot presented a prevalence of 0.10 (0.03-0.17) and a heterogeneity of 91.18%. The forest plot of the leg region was based on seven studies, which presented a prevalence of 0.01 (0.01-0.01) and a heterogeneity of 96.18%. Conclusions: This review and meta-analysis showed that, in studies that analyzed nerve compressions, the prevalence was low in the thigh and leg regions, while in the gluteal region, it was slightly higher. This is mainly due to the PM region and its different variants. We believe that it is important to analyze all the variant regions defined in this study and that surgeons treating the lower limb should be attentive to these possible scenarios so that they can anticipate possible surgical situations and thus avoid surgical complications.

Single incision, minimally invasive fasciotomy of the anterior and lateral leg compartments with decompression of the superficial peroneal nerve

BACKGROUND

There is a considerable overlap of symptoms between chronic exertional compartment syndrome (CECS) of the anterior and lateral compartments of the lower leg and entrapment neuropathy of the superficial peroneal nerve (SPN). We describe a minimally invasive, single incision surgical technique for release of both the compartments and the SPN in the same setting. The operative technique involves a minimal anterolateral approach at the level where the SPN pierces the subcutaneous fascia.

METHODS

Nineteen patients were operated with the method and 24 anterolateral compartments (5 cases with bilateral CECS) were released. Anterior and lateral, proximal and distal fasciotomies were performed sequentially with the use of a specific instrument designed for carpal tunnel release (KnifeLight®, Stryker). This is a modification of a fasciotome with an intergrated light source which allows for transillumination of the subcutaneous tissues. The SPN and its main branches with their anatomical variations were explored and decompressed at the same setting.

RESULTS

Patients who met the inclusion criteria were reviewed at one year postoperatively with a Numeric Analog Pain Scale (NAS) and the Linkert satisfaction scale. There were 5 men and 10 women, aged 35.7 (21-60) years. The NAS scores improved by a mean 6 points (p<0.0001) postoperatively and 86.6% (13/15) of the patients were either satisfied or very satisfied with the operation. There were no intraoperative complications. There were two patients with SPN neuropathy symptoms postoperatively, one of whom required revision surgery. One patient had recurrence of less intense symptoms in the first postoperative year with no need for reoperation.

CONCLUSIONS

The simultaneous release of the anterolateral compartment of the leg and decompression of the SPN with the described technique was safe and effective. It combined the advantages of a single, minimally invasive approach with the subcutaneous transillumination, and had a high patient satisfaction and a low recurrence rate.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

The Intraseptal Course of the Superficial Peroneal Nerve: An Anatomic Study

BACKGROUND

Anatomic and clinical studies show many variants of the superficial peroneal nerve (SPN) course and branching within the compartments and at the suprafascial layer. The anatomy of the transition zone from the compartment to the subcutaneous layer has been occasionally described in the literature, mainly in studies reporting the intraseptal SPN variant in 6.6% to 13.6% of patients affected by the SPN entrapment syndrome. Despite the little evidence available, the knowledge of the transition zone is relevant to avoid iatrogenic lesions to the SPN during fasciotomy, open approaches to the leg and ankle, and SPN decompression. Our anatomic study aimed to describe the SPN transition site and to evaluate the occurrence of a peroneal tunnel and of an intraseptal SPN variant.

METHODS

According to the institutional ethics committee requirements, 15 fresh-frozen lower limbs were dissected to study the SPN course and its branching, focusing on the transition site to the suprafascial layer.

RESULTS

The SPN was located in the anterior compartment in 2 cases and in the lateral in 13. An intraseptal tunnel was present in 10 legs (66%), at a mean distance of 10.67 cm from the lateral malleolus. Its mean length was 2.63 cm. The tunnel allowed the passage of the main SPN in 8 cases and of its branches in two. In the remaining 5 legs (33%), the SPN pierced a crural fascia window.

CONCLUSION

In our sample a higher rate than expected of intraseptal SPN variants was found.

CLINICAL RELEVANCE

The knowledge of the anatomy of the SPN course and intraseptal variant is relevant to avoid iatrogenic lesions during operative dissection. Further studies are needed to evaluate the effective prevalence of an intraseptal tunnel, independently from the SPN entrapment syndrome, and how to avoid associated iatrogenic complications.

The comprehensive review of the neurovascular supply of the ankle joint: clinical implications

The rupture of ligament in the lateral part of ankle joint is a common injury and can lead to chronic ankle instability and lead to ankle osteoarthritis. Ankle arthroscopy is considered as a standard option to treat various ankle problems due to the need for only minimal incisions and fewer complications when compared to open surgery. However, there are complications associated with arthroscopic surgery e.g. damage to the anatomical structures around the portal placement areas. The present review provides anatomical knowledge of the superficial and deep neurovascular structures in the ankle region. These structures are important when ankle surgery is performed in order to avoid any intraoperative injury and prevent any complication following surgery.

Surgical Tips for Performing Open Fasciotomies for Chronic Exertional Compartment Syndrome of the Leg

Chronic exertional compartment syndrome (CECS) of the leg is a debilitating condition that has previously been characterized in athletes and military personnel. The results of surgical management in these patient populations have previously been published with inconsistencies in surgical methods and patient outcomes noted. While endoscopic and minimally invasive techniques have been described, a detailed description of a "standard" open, 2-incision lateral and single-incision medial technique for the treatment of CECS has not been previously published. The purpose of this technique article is to highlight several tips and considerations related to this procedure in the hopes of standardizing treatment and potentially improving patient outcomes. Level of Evidence: Level V, expert opinion.

Weber C ankle fractures with tibiofibular diastasis: syndesmosis-only fixation

OBJECTIVES:

To evaluate syndesmosis-only fixation in Weber C ankle fractures with tibiofibular diastasis and to assess the need for additional fibular fixation.

METHODS:

Twenty-one patients with Weber C ankle fractures and tibiofibular diastasis were followed for at least 24 months after treatment. In treatment of the Weber C fractures, only a syndesmosis screw was used through a mini open lateral incision if the syndesmosis could be anatomically reduced and fibular length and rotation could be restored. At follow-up, anteroposterior tibiofibular distance, lateral fibular distance, medial mortise distance and fracture healing were compared and patients were clinically evaluated using the Olerud and Molander ankle scale scoring system.

RESULTS:

The average duration of follow-up was 49 months and the decreases in anteroposterior tibiofibular distance and lateral fibular distance were statistically significant. At the last follow-up the average clinical score was 86. Ankle mortise was reduced at follow-up in all cases except one, which resulted in a late diastasis.

CONCLUSIONS:

Syndesmosis-only fixation can be an effective method of treating Weber type-C lateral malleolar fractures with syndesmosis disruption in cases where intraoperative fibular length can be restored and anatomical syndesmosis reduction can be achieved. Level of Evidence IV, Case Series.

Selective Denervation for Persistent Knee Pain After Total Knee Arthroplasty: A Report of 50 Cases

BACKGROUND

Despite the general success of total knee arthroplasty (TKA), up to 20% of patients report dissatisfaction following surgery. One potential cause of this dissatisfaction is residual pain secondary to neuroma formation in the sensory nerve branches that innervate the knee. We found, after performing a retrospective review, that up to 9.7% of patients following primary TKA and up to 21% of revision cases exhibited persistent knee pain attributable to neuroma formation. Despite the high incidence of this pathology, little is known about the effective diagnosis or treatment of neuroma formation following TKA.

METHODS

Between 2011 and 2014, 50 patients with persistent symptomatic neuroma pain following TKA underwent selective denervation. These patients had demonstrated the appropriate selection criteria and had failed conservative management. Patients were evaluated by the visual analog scale pain score and the Knee Society Score to determine the outcome of the described treatment.

RESULTS

Thirty-two patients (64%) rated their outcome as excellent, 10 (20%) as good, 3 (6%) as fair, and 2 (4%) reported no change. The mean visual analog scale pain score was improved from 9.4 ± 0.8 to 1.1 ± 1.6 following surgery (P ≤ .001). The mean Knee Society Scores increased from 45.5 ± 14.3 to 94.1 ± 8.6 points (P ≤ .0001). Three patients (6%) required the second neurectomy due to recurrent pain and received excellent pain relief postoperatively. There were 2 complications of superficial skin peri-incisional hyperemia related to dressings. Average follow-up duration was 24 months (range, 16-38 months).

CONCLUSION

Our study suggests that selective denervation provides an effective and long-lasting option for the management of this pathology.

Entrapment of the Superficial Peroneal Nerve Following a Distal Fibula Fracture

Although peripheral nerve injury may result from fractures involving the long bones, bony entrapment of peripheral nerves is infrequently encountered. This report demonstrates a rare case of superficial peroneal nerve entrapment between 2 fracture ends of the distal fibula following a closed ankle fracture resulting from a supination-external rotation mechanism.

LEVELS OF EVIDENCE

Therapeutic, Level IV: Case report.

Decompression of the superficial peroneal nerve: clinical outcomes and anatomical study

OBJECTIVE

The authors of this study sought to determine the outcomes of patients undergoing superficial peroneal nerve (SPN) release to treat lower-extremity pain and describe consistent anatomical landmarks to direct surgical planning.

METHODS

This retrospective cohort study examined 54 patients with pain in the SPN distribution who were treated with decompression between 2011 and 2014. Patients rated pain and the effect of pain on quality of life (QOL) on the visual analog scale (VAS) from 0 to 10. Scores were then converted to percentages. Linear regression analysis was performed to assess the impact of the preoperative effect of pain on QOL, age, body mass index (BMI), and preoperative duration of pain on the postoperative effect of pain on QOL. Measurements were made intraoperatively in 13 patients to determine the landmarks for identifying the SPN.

RESULTS

A higher BMI was a negative predictor for improvement in the effect of pain on QOL. A decrease in pain compared with the initial level of pain suggested a nonlinear relationship between these variables. A minority of patients (7 of 16) with a preoperative pain VAS score ≤ 60 reported less pain after surgery. A large majority (30 of 36 patients) of those with a preoperative pain VAS score > 60 reported improvement. Intraoperative measurements demonstrated that the SPN was consistently found to be 5 ± 1.1, 5 ± 1.1, and 6 ± 1.2 cm lateral to the tibia at 10, 15, and 20 cm proximal to the lateral malleolus, respectively.

CONCLUSIONS

A majority of patients with a preoperative pain VAS score > 60 showed a decrease in postoperative pain. A higher BMI was associated with less improvement in the effect of pain on QOL. This information can be useful when counseling patients on treatment options. Based on the intraoperative data, the authors found that the SPN can be located at reliable points in reference to the tibia and lateral malleolus.

Current Diagnosis and Treatment of Superficial Fibular Nerve Injuries and Entrapment

The superficial peroneal nerve is now known as the superficial fibular nerve (SFN). Identification and treatment of entrapment of the SFN are important topics of discussion for foot and ankle surgeons, because overlooking the diagnosis can lead to permanent nerve damage. With the proper tools and skills, surgeons are able to help patients with symptomatic SFN entrapment, patients who often present in some degree of desperation, with the peripheral nerve surgeon as a last resort.

Entrapment of the superficial peroneal nerve: an anatomical insight

Entrapment of the superficial peroneal nerve is an uncommon neuropathy that may occur because of mechanical compression of the nerve, usually at its exit from the crural fascia. The symptoms include sensory alterations over the distribution area of the superficial peroneal nerve. Clinical examination, electrophysiologic findings, and imaging techniques can establish the diagnosis. Variations in the superficial peroneal sensory innervation over the dorsum of the foot may lead to variable results during neurologic examination and variable symptomatology in patients with nerve entrapment or lesions. Knowledge of the nerve's anatomy at the lower leg, foot, and ankle is of essential significance for the neurologist and surgeon intervening in the area.

Entrapment neuropathy about the foot and ankle: an update

Occurrences of entrapment neuropathies of the lower extremity are relatively infrequent; therefore, these conditions may be underappreciated and difficult to diagnose. Understanding the anatomy of the peripheral nerves and their potential entrapment sites is essential. A detailed physical examination and judicious use of imaging modalities are also vital when establishing a diagnosis. Once an accurate diagnosis is obtained, treatment is aimed at reducing external pressure, minimizing inflammation, correcting any causative foot and ankle deformities, and ultimately releasing any constrictive tissues.

Minimally invasive plate osteosynthesis in type B fibular fractures versus open surgery

BACKGROUND

In traumatology, the search for better surgical access points has led to the increased use of the minimally invasive plate osteosynthesis (MIPO) technique. There are few studies on the treatment of distal fibular fractures with MIPO. Locking compression plates (LCP) for distal fibular fractures is generally applied after open reduction, but may involve complications to the surgical wound. In this study, we compared two groups of patients receiving either ORIF or MIPO, in order to analyse the advantages and disadvantages of the two techniques.

MATERIALS AND METHODS

Two homogeneous groups of patients (18 + 18) received LCP for distal fractures of the fibula, type B, according to AO. Group A patients underwent open surgery, whereas Group B patients received plates applied with the MIPO technique. Both groups were examined physically and radiographically 1 and 3 months after the two types of procedure and then 1 year later, with functional assessment according to Olerud and Molander.

RESULTS

ROM Group A: 5° reduction in tibiotarsal extension in 8 patients and 5° in supination in 1 patient; Group B: 5° reduction in extension in 7 cases. Mean healing time: 3 months (range 2-4) in Group A and 2.9 (range 2-4) in Group B. Dehiscence of the surgical wound was observed in five Group A patients, but none in Group B. Functional assessment according to Olerud and Molander was 87.4 points in Group A (range 80-100) and 95.6 in Group B (range 82-100).

CONCLUSIONS

We believe that the MIPO technique for distal fractures of the fibula should be used more often, especially if soft tissue is in a critical condition. Healing times should be reduced in the more complex cases. It is important that the learning curve should be improved, to minimize exposure to radioscopy and possible damage to the superficial fibular nerve.

Joint denervation and neuroma surgery as joint-preserving therapy for ankle pain

Partial joint denervation or surgical neuroma therapy are alternative concepts to treat pain around the ankle joint that preserve joint function and relieve pain by interrupting neural pathways that transmit pain impulses from the joint to the brain. This review article summarizes the indication, anatomic background, operative techniques, and clinical results of joint denervation or neuroma surgery, which, although rarely reported and used, may provide a valuable alternative treatment in selected patients with neurogenous problems around the ankle.

Percutaneous plating of the distal tibia and fibula: risk of injury to the saphenous and superficial peroneal nerves

OBJECTIVES

To assess the risk of injury to the superficial peroneal nerve, saphenous nerve, and saphenous vein in percutaneous fixation of the distal fibula and tibia.

METHODS

Ten adult cadaver lower extremities were instrumented with precontoured periarticular plates for the distal tibia and fibula. Plates were inserted percutaneously along the medial distal tibia and lateral fibula. Smooth wires were inserted percutaneously into each screw hole. Dissection of the superficial peroneal nerve, saphenous nerve, and saphenous vein was performed along their respective course. The position of the neurovascular structures relative to the smooth wires was recorded.

RESULTS

The saphenous nerve and vein had a predictable course along the medial aspect of the ankle. Both structures were injured in every specimen. This occurred consistently at 2.0 to 4.7 cm from the tip of the medial malleolus. The superficial peroneal nerve demonstrated large variance in the exit point from the lateral compartment crural fascia, exiting at an average of 11.6 cm from the tip of the lateral malleolus. Injury occurred in a single specimen at 11.5 cm from this point.

CONCLUSIONS

The superficial peroneal nerve, saphenous nerve, and saphenous vein are at risk during percutaneous submuscular plating of the distal fibula and tibia. Careful dissection proximally for the fibula and distally for the tibia can minimize the risk of damage to these structures.

Anterior transposition of the superficial peroneal nerve branch during the internal fixation of the lateral malleolus

BACKGROUND

Because of the anatomic variations of the superficial peroneal nerve (SPN), it has long been stressed that caution should be exercised at the time of open reduction and internal fixation (ORIF) of the lateral malleolus.

METHODS

Blair and Botte described type B intermediate dorsal cutaneous nerve (IDCN) in which the SPN penetrates crural fascia posterior to the fibula about 5 cm proximal to the joint and crosses the lateral border of the fibulae. We hypothesized that the type B IDCN is especially vulnerable to direct surgical injury if present and the anterior transposition of this nerve may decrease the incidence of symptoms related to the SPN injury. Fifty-three ankle fractures in 53 adult patients treated by the ORIF of lateral malleolus using the lateral approach between the periods from May 2001 to December 2006 were included. Intraoperative documentation about the presence of the type B IDCN variant at the surgical field was performed, and preoperative and postoperative sensory changes were carefully evaluated.

RESULTS

We encountered Blair type B variant in 7 cases (12%). The IDCN was carefully dissected and transposed anteriorly before the plating. One of these seven patients had sensory deficit preoperatively, and it was recovered spontaneously 5 months after operation. There was one patient whose IDCN was inadvertently severed, and it was repaired. At the time of last follow-up, only partial recovery of the sensory deficit was noted. Five of seven patients did not show any neurologic deficit with anterior transposition.

CONCLUSION

Recognition and anterior transposition of the type B IDCN could reduce the incidence of the SPN nerve injuries during the ORIF of the lateral malleolar fractures.

Anatomic site for proximal tibial nerve compression: a cadaver study

Primary compression of the tibial nerve beneath the fibromuscular sling of the origin of the soleus muscle is rarely discussed in the literature. To evaluate the location and characteristics of the soleal fibromuscular sling and its relationship to the tibial nerve, 36 cadaver limbs were dissected. The leg length, location of soleal fibromuscular sling, presence of a thickened fibrous band at the soleal sling, and narrowing in the tibial nerve were recorded. The average leg length was 47.8 cm (SD +/- 4.16). The fibromuscular soleal sling was 9.3 cm (SD +/- 1.44) distal to the medial tibial plateau. Although 56% (20/36) of specimens had a fibrous band, only 8% (3/36) demonstrated a focal narrowing directly under this fascial sling. This study demonstrates that the fibromuscular sling of the soleus muscle may act as a potential compression site of the tibial nerve. These findings offer insight and potential hope for those patients who have persistent plantar numbness after tarsal tunnel decompression and for those patients with plantar numbness who also have weakness of toe flexion.

Intraseptal superficial peroneal nerve

Knowledge of the anatomy of the superficial peroneal nerve (SPN) is necessary for surgeons caring for patients with lower extremity pain after ankle, leg, or knee injuries, for athletes with exertional compartment syndrome, and those having reconstructive microsurgery with either soft tissue or vascularized fibular flaps. The anatomy of the SPN is known to be that of a peripheral nerve traveling in the lateral compartment of the lower leg. Recently, clearer descriptions of its variability have documented that between 27 and 43% of patients have the SPN in either the anterior compartment or both the anterior and the lateral compartment of the leg. The present observations record the location of the SPN within the septum that separates the anterior from the lateral compartment. Awareness of this unusual variant location will enable the surgeon to find and preserve the SPN during fasciotomy, neurolysis, neuroma resection, or bony and soft tissue reconstruction.

The clinical importance of variations in the surgical anatomy of the superficial peroneal nerve in the mid-third of the lateral leg

The superficial peroneal nerve (SPN) provides fundamental motor and sensory innervation to the leg and foot. A variety of surgical procedures is performed in the vicinity of this nerve, requiring that the surgeon be familiar with its specific anatomy. We dissected 111 legs to define the anatomic position of the SPN and found that the nerve had 4 distinct variations in location. In 77 (69.4%) specimens, the nerve coursed within the lateral compartment of the leg, while in 18 (16.2%) of the legs, the nerve split and contained branches in both the lateral and anterior compartments. The nerve in 7 (6.3%) legs was found within the intermuscular septum, and in 9 (8.1%) of the specimens, the SPN traveled only within the anterior compartment. These results confirm 4 anatomic variants of the SPN, which will aid surgeons in locating the nerve in the lateral aspect of the leg.