Surgical treatment of lumbosacral plexus injuries

Lumbosacral Plexogram: An Aid to Reconstructive Nerve Possibilities in the Lower Extremity

The lumbosacral plexus is the network of nerves responsible for the motor and sensory function of the pelvis and lower limb. Our observation is that the anatomy of this plexus is less familiar to surgeons than that of the brachial plexus. Damage to the lumbosacral plexus and its terminal branches may have a significant impact on locomotion, posture, and stability. We have designed a visual representation of the lumbosacral plexus to aid clinicians treating peripheral nerve disorders. The utility is illustrated with a case report in which a patient underwent nerve transfers in the lower limb to restore function. A visual representation of the lumbosacral plexus is a valuable adjunct to a clinical examination and helps make sense of clinical signs. The color-coding of each root level and the arrangement of muscles from proximal to distal helps with visual recall. A clear assessment of complex lumbosacral plexus patients is essential for diagnosis and planning. As with the case described, a sound knowledge of the "plexogram" can identify solutions for complex patients and result in significant functional improvements. We hope it helps advance the field of nerve surgery and, particularly, nerve transfers.

Differentiating Lumbar Spinal Etiology from Peripheral Plexopathies

Clinicians have managed and treated lower back pain since the earliest days of practice. Historically, lower back pain and its accompanying symptoms of radiating leg pain and muscle weakness have been recognized to be due to any of the various lumbar spine pathologies that lead to the compression of the lumbar nerves at the root, the most common of which is the radiculopathy known as sciatica. More recently, however, with the increased rise in chronic diseases, the importance of differentially diagnosing a similarly presenting pathology, known as lumbosacral plexopathy, cannot be understated. Given the similar clinical presentation of lumbar spine pathologies and lumbosacral plexopathies, it can be difficult to differentiate these two diagnoses in the clinical setting. Resultingly, the inappropriate diagnosis of either pathology can result in ineffective clinical management. Thus, this review aims to aid in the clinical differentiation between lumbar spine pathology and lumbosacral plexopathy. Specifically, this paper delves into spine and plexus anatomy, delineates the clinical assessment of both pathologies, and highlights powerful diagnostic tools in the hopes of bolstering appropriate diagnosis and treatment. Lastly, this review will describe emerging treatment options for both pathologies in the preclinical and clinical realms, with a special emphasis on regenerative nerve therapies.

Exposure of the Lumbosacral Plexus by Using the Pararectus Approach: A Technical Note

BACKGROUND

Surgical exploration of the lumbosacral plexus is challenging. Previously described approaches reach from invasive open techniques with osteotomy of the ilium to laparoscopic techniques.

OBJECTIVE

To describe a novel surgical technique to explore lumbosacral plexopathies such as benign nerve tumors or iatrogenic lesions of the lumbosacral plexus in 4 case examples.

METHODS

We retrospectively evaluated 4 patients suffering from pathologies or injuries of the lumbosacral plexus between 2017 and 2019. The mean follow-up period after surgery was 23.5 (range 11-52) months. All patients underwent neurolysis of the lumbosacral plexus using the single incision, intrapelvic, extraperitoneal pararectus approach.

RESULTS

In all patients, the pathology of the lumbosacral plexus was successfully visualized, proving feasibility of the extraperitoneal pararectus approach for this indication. There were no major complications, and all patients recovered well.

CONCLUSION

The pararectus approach allows excellent visualization of the lumbar plexus and intrapelvic lesions of the femoral and sciatic nerves.

Bioinformatic analysis of circular RNA expression profiles in a rat lumbosacral spinal root avulsion model

Lumbosacral spinal root avulsion (LSRA) is a severe nerve injury that results in devastating dysfunction in the lower limb. Circular ribonucleic acids (circRNAs) have been reported to be implicated in a variety of diseases. However, the role of circRNAs in LSRA remains unclear. Here, we performed RNA sequencing (RNA-seq) to determine circRNA expression profiles in a rat LSRA model and further investigated their potential functions and the underlying mechanisms by bioinformatic analyses and in vitro experiments. In all, 1708 circRNAs were found to be differentially expressed in spinal cord tissues after LSRA (|fold change| ≥ 2 and p < 0.05), with 591 up-regulated 1117 down-regulated. Meanwhile, 2263 mRNAs were also indentified to be differentially expressed, of which 1471 were upregulated and 792 were downregulated. Eight randomly selected circRNAs and mRNA were successfully verified to be consistent the RNA-seq results by quantitative real-time polymerase chain reaction. Functional analyses based on gene ontology and Kyoto Encyclopedia of Genes and Genomes predicted the potential roles of differentially expressed circRNAs and mRNAs in LSRA, and circRNA/miRNA/mRNA interaction networks revealed that circRNA_7025, a down-regulated circRNA in LSRA, was targeted by two neuronal apoptosis-related miRNAs, rno-miR-1224 and rno-miR-326-5p. Further in vitro experiments revealed that circRNA_7025 protected against oxygen-glucose deprivation induced neuronal apoptosis via the circRNA_7025/miR-1224/miR-326-5p axis. In summary, our results revealed circRNA expression profiles and their potential functions in LSRA. These findings improve our understanding of the pathogenic mechanisms involved in LSRA and might enable us to identify new molecular targets for LSRA.

Surgical Interventions for Lumbosacral Plexus Injuries: A Systematic Review

Background:

Nerve reconstruction techniques for lumbosacral plexus (LSP) injuries vary. There are no clear treatment guidelines available, and summative evaluations of the literature discussing these surgeries are lacking. For these reasons, this investigation aimed to systematically review and consolidate all available literature discussing surgical interventions for LSP injuries and cohesively present patient-reported and objective postoperative outcomes.

Methods:

The authors conducted a systematic review using PubMed, Embase, Web of Science, ProQuest Dissertations and Theses Global (via Proquest.com), and ClinicalTrials.gov databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. After title and abstract screening, identified articles were read in full and selected for inclusion based on prespecified criteria.

Results:

Our literature search identified 8683 potential citations, and after duplicate removal, abstract screening, and full-text review, 62 studies remained meeting inclusion and exclusion criteria. Outcomes were extracted according to the location of injury and type of surgical repair. Injuries were classified into isolated femoral nerve injuries, isolated obturator nerve injuries, isolated sciatic nerve injuries, and multilevel LSP injuries. Surgical treatment was further classified into exploration with neurolysis, direct repair, nerve grafting, and nerve transfer surgery.

Conclusions:

Although results vary based on the location of the injury and the surgical technique used, nerve grafts and transfers demonstrated reasonable success in improving functional and pain outcomes. Overall, isolated femoral and obturator nerve injuries had the best outcomes reported with surgical treatment. Furthermore, incomplete sciatic nerve and multilevel LSP injuries had more reported surgical options and better outcomes than complete sciatic nerve injuries.

Novel Use of Nerve Branch to Sartorius as Donor for Intrapelvic Neurotization of the Sciatic Nerve and Its Contributions

BACKGROUND

Sciatic nerve injuries are relatively infrequent but extremely disabling for the patient. As injury to this nerve is relatively infrequent, there is little about its repair in the literature, especially within the pelvis.

METHODS

Twelve adult embalmed cadavers (24 sides) underwent exposure of the anteromedial thigh, inguinal region, and pelvic cavity. The sartorius muscle was identified in the anterior thigh, and its nerve branches from the femoral nerve were isolated and traced proximally to the femoral nerve trunk. The isolated sartorius nerve branches were further traced to the pelvic part of the femoral nerve. Next, the lumbosacral plexus was dissected on the posterior aspect of the pelvis so that its constituent parts were seen and followed distally to also visualize the most proximal part of the sciatic nerve. The previously dissected nerve branches to sartorius were then transposed to these constituent parts, and the ability for a tension-free anastomosis between these 2 nerves was evaluated.

RESULTS

The branches ranged in diameter from 1.89 to 3.1 mm (2.88 mm). The average length of the nerves was 17.3 cm. Transposition of these branches to all ventral rami of the lumbosacral plexus in the pelvis and proximal sciatic (intrapelvic) nerve was possible on all cadaveric sides.

CONCLUSIONS

Our cadaveric study found that nerve branches to the sartorius muscle can be transposed intrapelvically to the lumbosacral plexus and could provide tension-free anastomoses for neurotization procedures in patients with nerve injury.

Obturator to tibial nerve transfer via saphenous nerve graft for treatment of sacral plexus root avulsions: A cadaveric study

INTRODUCTION

In cases of sacral nerve avulsion injuries, proximal nerve stumps are not available because of its protected position in pelvis, and results of nerve repair or graft are unsatisfactory. Nerve transfer can reduce the regeneration time and improve the results of recovery.

HYPOTHESIS

The obturator nerve transfer to the tibial nerve via saphenous nerve graft is possible and feasible.

MATERIALS AND METHODS

Ten male adult cadaveric lower limbs dissected to identify the location of the anterior branch of obturator nerve, the saphenous nerve and the medial gastrocnemius branch. The saphenous nerve was cut from its origin and transferred to the anterior branch of obturator nerve. As well, it was cut distally and transferred to the medial gastrocnemius branch. After nerve coaptation, surface area and fascicle count were determined by histological methods.

RESULTS

In all limbs, the proximal and distal stumps of saphenous nerve were reached the anterior branch of obturator and the medial gastrocnemius branch, respectively without tension. The mean of fascicle number in the anterior branch of obturator nerve, proximal and distal stump of the saphenous nerve and stump of medial gastrocnemius nerve branch were 2.90±0.99, 4.50±2.70, 4.00±2.26 and 4.30±1.25, respectively.

DISCUSSION

This study showed that it is possible to transfer the obturator nerve to the medial gastrocnemius branch via saphenous nerve bridge; and their histological parameters are match in a good manner. Therefore, this technique is suggested for patients with sacral nerve avulsion injuries.

LEVEL OF EVIDENCE

IV, case series of cadaveric study.

Anatomical feasibility of anastomosing intercostal nerves (D10&D11) and subcostal nerve (D12) to S2 ventral root and lumbar plexus for management of bladder function after spinal cord injury

OBJECTIVE

The transfer of peripheral nerves originating above the level of injured spinal cord into the nerves/roots below the injury is a promising approach. It facilitates the functional recovery in lower extremity, bladder/bowel and sexual function in paraplegics. We assessed anatomical feasibility of transfer of lower intercostal nerves to S2 ventral root in human cadaver for management of neurogenic bladder dysfunction in patients with spinal cord injury.

METHODS

Study was performed in five formalin fixed cadavers. Cadavers were placed in prone position. A transverse incision was made along 11th ribs on both sides and 10th, 11th Intercostal nerves (ICN) and subcostal nerve were harvested up to maximum possible length. In four cadavers the ventral root of S2 was exposed by endoscope and in one by the standard open laminectomy. Intercostal nerves were brought down to lumbo-sacral region, S2 ventral root was cut cranially and feasibility of intercostal to S2 anastomosis was assessed.

RESULTS

The mean length of intercostal nerves was 18.4 cm for the 10th 19.5 cm for the 11th and 22.15 cm for the subcostal nerve. The length of harvested nerve and the nerve length necessary to perform sacral roots neurotization were possible in all cases by only by subcostal nerve while T11 and T10 ICN fall short of the required length.

CONCLUSION

For Spinal cord lesions located at the conus, subcostal nerve could be connected to ventral root of S2 in an attempt to restore bladder function while 10th and 11th ICN had enough length to neurotize lumbar plexus.

Factors associated with gait outcomes in patients with traumatic lumbosacral plexus injuries

PURPOSE

Lumbosacral plexus injuries usually occur in patients with severe, multiple traumas requiring intensive care, affecting gait function. The purpose of the present study was to identify the initial factors associated with gait outcome in lumbosacral plexus injuries caused by traumas.

METHODS

We retrospectively identified 664 patients with pelvic fractures caused by trauma between 2006 and 2017. The lumbosacral plexus injuries were electrodiagnostically confirmed in 30 patients (4.5%). Demographic, injury-related, fracture-related and electrodiagnostic factors were compared between patients with long-term unassisted gait outcomes to those with assisted gait outcomes, with an average of 27 months elapsing after the trauma.

RESULTS

Eleven patients (36.7%) remained in the assisted gait group during the follow-up period. Complex pelvic trauma, rather than the severity of trauma to the entire body, was associated with a poor gait outcome. Among the various causes of injury, pedestrians struck by vehicles were associated with assisted gait outcomes. The number of anatomic locations involved in pelvic fractures, pelvic ring instability by Tile classification, and the proportion of unstable sacral fractures were higher in patients with assisted gait outcomes compared with those having unassisted gait outcomes. Weaknesses in the initial hip extensor, knee flexor, ankle dorsiflexor and ankle plantar flexor were observed significantly more often in patients with assisted gait outcomes. The Dumitru and Wilbourn's scale of the anterior and posterior sacral plexus was significantly higher in the assisted gait group.

CONCLUSIONS

Gait outcome after lumbosacral plexus injury is associated with the range and stability of the pelvic fracture and the severity of the anterior and posterior sacral plexus injury. Poor gait outcome was associated with the severity of the trauma to the pelvis rather than that to the entire body.

Demystifying MR Neurography of the Lumbosacral Plexus: From Protocols to Pathologies

Magnetic resonance neurography is a high-resolution imaging technique that allows evaluating different neurological pathologies in correlation to clinical and the electrophysiological data. The aim of this article is to present a review on the anatomy of the lumbosacral plexus nerves, along with imaging protocols, interpretation pitfalls, and most common pathologies that should be recognized by the radiologist: traumatic, iatrogenic, entrapment, tumoral, infectious, and inflammatory conditions. An extensive series of clinical and imaging cases is presented to illustrate key-points throughout the article.

[Imaging of the lumbosacral plexus : Diagnostics and treatment planning with high-resolution procedures]

BACKGROUND

Technical advances in magnetic resonance (MR) and ultrasound-based neurography nowadays facilitate the radiological assessment of the lumbosacral plexus.

OBJECTIVE

Anatomy and imaging of the lumbosacral plexus and diagnostics of the most common pathologies.

MATERIAL AND METHODS

Description of the clinically feasible combination of magnetic resonance imaging (MRI) and ultrasound diagnostics, case-based illustration of imaging techniques and individual advantages of MRI and ultrasound-based diagnostics for various pathologies of the lumbosacral plexus and its peripheral nerves.

RESULTS

High-resolution ultrasound-based neurography (HRUS) is particularly valuable for the assessment of superficial structures of the lumbosacral plexus. Depending on the examiner's experience, anatomical variations of the sciatic nerve (e. g. relevant in piriformis syndrome) as well as more subtle variations, for example as seen in neuritis, can be sonographically depicted and assessed. The use of MRI enables the diagnostic evaluation of more deeply located nerve structures, such as the pudendal and the femoral nerves. Modern MRI techniques, such as peripheral nerve tractography allow three-dimensional depiction of the spatial relationship between nerves and local tumors or traumatic alterations. This can be beneficial for further therapy planning.

CONCLUSION

The anatomy and pathology of the lumbosacral plexus can be reliably imaged by the meaningful combination of MRI and ultrasound-based high resolution neurography.

Obturator Nerve Transfer to the Branch of the Tibial Nerve Innervating the Gastrocnemius Muscle for the Treatment of Sacral Plexus Nerve Injury

BACKGROUND:

Lower-limb function is severely impaired after sacral plexus nerve injury. Nerve transfer is a useful reconstructive technique for proximal nerve injuries.

OBJECTIVE:

To investigate the clinical effectiveness and safety of transferring the ipsilateral obturator nerve to the branch of the tibial nerve innervating the medial head of the gastrocnemius muscle to recover knee and ankle flexion.

METHODS:

From 2007 to 2011, 5 patients with sacral plexus nerve injury underwent ipsilateral obturator nerve transfer as part of a strategy for surgical reconstruction of their plexuses. The mean patient age was 31.4 years (range, 19-45 years), and the mean interval from injury to surgery was 5.8 months (range, 3-8 months). The anterior branch of the obturator nerve was coapted to the branch of the tibial nerve innervating the medial head of the gastrocnemius muscle by autogenous nerve grafting.

RESULTS:

Patient follow-up ranged from 24 to 38 months. There were no complications related to the surgery. Three patients recovered to Medical Research Council grade 3 or better in the medial head of the gastrocnemius muscle. Thigh adduction function was not affected in any patient.

CONCLUSION:

Knee and ankle flexion can be achieved by transferring the anterior branch of the obturator nerve to the branch of the tibial nerve innervating the medial head of the gastrocnemius muscle, which is useful for balance. This procedure can be used as a new method for treating sacral plexus nerve injury.

Repair and regeneration of lumbosacral nerve defects in rats with chitosan conduits containing bone marrow mesenchymal stem cells

OBJECTIVES

Despite the great progress in surgical treatment of lumbosacral nerve injuries caused by high-energy trauma, functional recovery remains poor and insufficient. Bone marrow mesenchymal stem cells (BMSCs), which express neurotrophic factors and can also differentiate into nerve cells, have potential as an effective alternative therapy for lumbosacral nerve defects. The aim of the present study was to evaluate the functional recovery, nerve regeneration, motor neuron survival and apoptosis after lumbosacral nerve transection in rats receiving BMSC transplantation into the chitosan conduit.

METHODS

The right L4-L6 nerve roots of rats were transected and bridged with three 1-cm-long chitosan conduits, which were further injected with the BMSCs (MSC-treated group) or culture medium (DMEM group). The nerve regeneration and motor function recovery were assessed by the sciatic functional index (SFI) and analysed electrophysiologically and morphologically.

RESULTS

At 6 and 12 weeks after surgery, the SFI values in MSC-treated group were significantly higher than those in DMEM group (P≤0.05). The peak amplitude of CMAP (compound muscle action potential) and nerve conduction velocity in MSC-treated group were significantly higher than that in DMEM group (P≤0.01), while the latency of CMAP onset in MSC-treated group was significantly shorter than that in DMEM group (P≤0.01). The diameter of the myelinated fibres and thickness of the myelin sheath in MSC-treated group were significantly higher than those in DMEM group (P≤0.05). There was no difference in the number of motor neurons in the anterior horn of the spinal cord at 6 weeks post-operation (P>0.05), while the number of motor neurons was significantly greater in MSC-treated group than that in DMEM group at 12 weeks post-operation (P≤0.001). The number of apoptotic cells was also significantly lower (P≤0.01).

CONCLUSIONS

The results of the present study showed that BMSCs treatment improved lumbosacral nerve regeneration and motor function. In addition, our data suggested that BMSCs inhibited motor neuron apoptosis, and improved motor neuron function and survival in the anterior horn of the spinal cord.

Zhang, Yang D, Chen A. The effect of severing a normal S1 nerve root to use for reconstruction of an avulsed contralateral lumbosacral plexus

The aim of this study was to evaluate the feasibility of using the intact S1 nerve root as a donor nerve to repair an avulsion of the contralateral lumbosacral plexus. Two cohorts of patients were recruited. In cohort 1, the L4–S4 nerve roots of 15 patients with a unilateral fracture of the sacrum and sacral nerve injury were stimulated during surgery to establish the precise functional distribution of the S1 nerve root and its proportional contribution to individual muscles. In cohort 2, the contralateral uninjured S1 nerve root of six patients with a unilateral lumbosacral plexus avulsion was transected extradurally and used with a 25 cm segment of the common peroneal nerve from the injured leg to reconstruct the avulsed plexus.

The results from cohort 1 showed that the innervation of S1 in each muscle can be compensated for by L4, L5, S2 and S3. Numbness in the toes and a reduction in strength were found after surgery in cohort 2, but these symptoms gradually disappeared and strength recovered. The results of electrophysiological studies of the donor limb were generally normal.

Severing the S1 nerve root does not appear to damage the healthy limb as far as clinical assessment and electrophysiological testing can determine. Consequently, the S1 nerve can be considered to be a suitable donor nerve for reconstruction of an avulsed contralateral lumbosacral plexus.

Cite this article: Bone Joint J 2015; 97-B:358–65.

Anterior cornual motoneuron regression pattern after sacral plexus avulsion in rats

BACKGROUND

Sacral plexus avulsions lead to severe disability in patients and remain a thorny clinical problem due to the lack of anatomical, experimental and clinical studies. Attempts have been made to treat lumbosacral plexus injuries with such operations as direct anastomosis of the ends of injured sacral plexuses, and certain therapeutic effects were achieved. To further explore the degeneration pattern of anterior cornual motoneurons and determine the best time for treatment, we carried out this study.

METHODS

We randomly assigned 60 SD rats into six groups (group A-F), with ten rats per group. The A, B, C, D, E, F groups included animals that received operation for L4-L6 nerve root avulsion at 2, 4, 6, 8, 10 and 12 weeks respectively. We measured the apoptosis of motor neurons in the anterior corn through hematoxylin-eosin (HE) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, and found that after sacral plexus avulsions, motor neurons in the anterior horn of the spinal cord gradually reduced and the apoptosis index gradually increased as the time went by.

RESULTS

Survival rates of motoneurons at 2, 4, 6, 8, 10, and 12 weeks after avulsion were (92.1 ± 4.7)%, (83.6 ± 3.7)%, (43.6 ± 4.2)%, (32.1 ± 3.5)%, (18.4 ± 3.7)% and (12.1 ± 3.3)%, respectively. The difference was most significant at week 6.

CONCLUSION

Week 6 after injury is probably the deadline for surgical repair of sacral plexus avulsions.

Unaffected contralateral S1 transfer for the treatment of lumbosacral plexus avulsion

INTRODUCTION

This study describes a new surgical strategy for lumbosacral plexus avulsion by transfer of the unaffected contralateral S1 nerve root.

METHODS

A surgical reconstruction of the sacral nerve was performed on a 10-year-old boy with left lumbosacral plexus avulsion. The unaffected S1 nerve root (right side) is severed extradurally for transfer. A 25-cm long nerve graft from the common peroneal nerve of the affected side was used as donor nerve. One end of the nerve graft was anastomosed to the proximal stump of the right-sided extradural S1 nerve. The distal end of the nerve graft was divided into two fascicles and anastomosed to the left-sided inferior gluteal nerve and the branch of the sciatic nerve innervating the left-sided hamstrings.

RESULTS

According to motor score of the British Medical Research Council (MRC) system, the strength of glutei and hamstrings improved to the level of M3 1.5 years after surgery.

CONCLUSIONS

The extradural S1 nerve root in the unaffected side can be considered as a suitable donor nerve for transfer in patients with root avulsion of the lumbar or sacral nerve plexus.

High-resolution 3-T MR neurography of the lumbosacral plexus

The lumbosacral plexus comprises a network of nerves that provide motor and sensory innervation to most structures of the pelvis and lower extremities. It is susceptible to various traumatic, inflammatory, metabolic, and neoplastic processes that may lead to lumbrosacral plexopathy, a serious and often disabling condition whose course and prognosis largely depend on the identification and cure of the causative condition. Whereas diagnosis of lumbrosacral plexopathy has traditionally relied on patients' medical history, clinical examination, and electrodiagnostic tests, magnetic resonance (MR) neurography plays an increasingly prominent role in noninvasive characterization of the type, location, and extent of lumbrosacral plexus involvement and is developing into a useful diagnostic tool that substantially affects disease management. With use of 3-T MR imagers, improved coils, and advanced imaging sequences, which provide exquisite spatial resolution and soft-tissue contrast, MR neurography provides excellent depiction of the lumbrosacral plexus and its peripheral branches and may be used to confirm a diagnosis of lumbrosacral plexopathy with high accuracy or provide superior anatomic information should surgical intervention be necessary.

In lumbosacral plexus injuries can we identify indicators that predict spontaneous recovery or the need for surgical treatment? Results from a clinical study on 72 patients

Background

Post-traumatic lumbosacral plexus injuries seem to be rare events, spontaneously recovering in high percentage: as surgery is often challenging and results in poor outcome, many Authors have advocated conservative treatment only. Nevertheless surgery should not be ruled out: in invalidating injuries, it can restore basic function in the lower extremities.

Therefore, it might be necessary to establish guidelines for the management and the indication to surgery in such cases.

This study aims to identify indicators predicting spontaneous recovery or the need for surgery.

Method

The clinical and radiological data of 72 patients with a post-traumatic lumbosacral plexus injury were reviewed. A follow up equal or superior to 3 years is available in 42 cases.

Results

Lumbosacral plexus injuries mostly occurred during road accidents. The incidence of associated lesions was relevant: bone injuries were found in 85% of patients, internal lesions in 30% and vascular injuries in 8%.

Lumbosacral trunk and sacral plexus palsies were the most frequent injury patterns.

Root avulsions were revealed in 23% of cases and only in sacral plexus and complete lumbosacral plexus injuries: L5 and S1 were the roots more prone to avulsions.

About 70% of cases recovered spontaneously, mostly in 18 months. Spontaneous recovery was the rule in lumbar plexus and lumbosacral trunk injuries (where root avulsions never occurred) or in sacral and complete lumbosacral plexus palsies due to compression injuries.

The causative mechanism correlated with the injury pattern, the associated bone injury being often predictive of the severity of the nerve injury.

Lumbosacral plexus injuries occurred in car crashes were generally associated with fractures causing compression on the nerves, thus resulting in injuries often amenable of spontaneous recovery.

Motorcycle accidents implied high kinetic energy traumas where traction played an important role, as the high percentage of sacroiliac joint separations demonstrated (found in more than 50% of cases and always associated to root avulsions).

Loss of sphincteral control and excruciating leg pain were also invariably associated with avulsions.

Conclusions

Clinical and radiological data can help to predict the occurrence of spontaneous recovery or the need for surgery in post-traumatic lumbosacral plexus injuries.

Contralateral L-6 nerve root transfer to repair lumbosacral plexus root avulsion: experimental study in rhesus monkeys

Object

Nerve transfer is used for brachial plexus injuries but has rarely been applied to repairs in the lower extremities. The aim of this study was to evaluate the feasibility and effectiveness of using the contralateral L-6 nerve root to repair lumbosacral plexus root avulsions.

Methods

Eighteen rhesus monkeys were randomized into 3 groups. In the experimental group, the left L4–7 and S-1 nerve roots were avulsed and the right L-6 nerve root was transferred to the left inferior gluteal nerve and the sciatic nerve branch innervating the hamstrings. In the control group, the left L4–7 and S-1 nerve roots were avulsed and nerve transfer was not performed. In the sham operation group, the animals underwent a procedure that did not involve nerve avulsion and nerve transfer. Functional outcomes were measured by electrophysiological study, muscle mass investigation, and histological study.

Results

The mean amplitudes of the compound muscle action potentials from the gluteus maximus and biceps femoris in the experimental group were higher than those in the control group but lower than those in the sham group (p < 0.05). The muscle mass and myofiber cross-sectional area of these muscles were heavier and larger than those in the control group (p < 0.05). The number of myelinated nerve fibers of the inferior gluteal nerve and the branch of the sciatic nerve innervating the hamstrings in the control group was significantly smaller than the number in the experimental and sham groups (p < 0.01).

Conclusions

In this animal model, the contralateral L-6 (analogous to S-1 in humans) nerve root can be used to repair lumbosacral plexus root avulsion.

Reconstruction of sciatic nerve after traumatic injury in humans - factors influencing outcome as related to neurobiological knowledge from animal research

Background

The aim was to evaluate what can be learned from rat models when treating patients suffering from a sciatic nerve injury.

Methods

Two patients with traumatic sciatic nerve injury are presented with examination of motor and sensory function with a five-year follow-up. Reconstruction of the nerve injury was performed on the second and third day, respectively, after injury using sural nerve grafts taken from the injured leg. The patients were examined during follow-up by electromyography (EMG), MRI and functionalMRI (fMRI) to evaluate nerve reinnervation, cell death in dorsal root ganglia (DRG) and cortical activation; factors that were related to clinical history in the patients.

Results

One patient regained good motor function of the lower leg and foot, confirmed by EMG showing good activation in the leg muscles and some reinnervation in the foot muscles, as well as some sensory function of the sole of the foot. The other patient regained no motor (confirmed by EMG) or sensory function in the leg or foot. Factors most influential on outcome in two cases were type of injury, nerve gap length and particularly type of reconstruction. A difference in follow-up and rehabilitation likely also influence outcome. MRI did not show any differences in DRG size of injured side compared to the uninjured side. fMRI showed normal activation in the primary somatosensory cortex as a response to cutaneous stimulation of the normal foot. However, none of the two patients showed any activation in the primary somatosensory cortex following cutaneous stimulation of the injured foot.

Conclusions

In decision making of nerve repair and reconstruction data from animal experiments can be translated to clinical practice and to predict outcome in patients, although such data should be interpreted with caution and linked to clinical experience. Rat models may be useful to identify and study factors that influence outcome after peripheral nerve repair and reconstruction; procedures that should be done correctly and with a competent team. However, some factors, such as cognitive capacity and coping, known to influence outcome following nerve repair, are difficult to study in animal models. Future research has to find and develop new paths and techniques to study changes in the central nervous system after nerve injury and develop strategies to utilize brain plasticity during the rehabilitation.

Critical analysis of extra peritoneal antero-lateral approach for lumbar plexus

Lesions of lumbar plexus are uncommon and descriptions of surgical access are derived from vertebral spine approaches.

METHOD

The extraperitoneal anterolateral approach to the lumbar plexus was performed in six adult fresh cadavers. The difficulties on dissection were related.

RESULTS

An exposure of all distal elements of lumbar plexus was possible, but a cranial extension of the incision was needed to reach the iliohypogastric nerve in all cases. Ligation of vessels derived from common iliac artery was necessary for genitofemoral and obturator nerves exposure in two cases. The most proximal part of the lumbar roots could be identified only after dissection and clipping of most lumbar vessels.

CONCLUSION

The extraperitoneal anterolateral approach allows appropriate exposure of terminal nerves of lumbar plexus laterallly to psoas major muscle. Cranial extension of the cutaneous incision may be necessary for exposure of iliohypogastric nerve. Roots exposure increases the risk of vascular damage.

Risk factors for lumbosacral plexus palsy related to pelvic fracture

STUDY DESIGN

A retrospective study.

OBJECTIVE

We assessed risk factors for lumbosacral plexus palsy related to pelvic fracture that can be evaluated during the acute injury phase with diagnostics such as computed tomography (CT).

SUMMARY OF BACKGROUND DATA

Many patients with pelvic fracture are in vital shock, with polytrauma and loss of consciousness, making an accurate neurologic examination very difficult in the emergency room.

METHODS

This study included 22 patients who had AO classification type B or C pelvic fractures. The 22 patients had 27 posterior osteoligamentary lesions. The average injury severity score (ISS) was 27.5 (range, 16-50). Age, sex, ISS, suicidal jump, longitudinal displacement, sacral transverse fracture, pubic fracture, lumbar transverse process fracture, type of pelvic fracture (AO), and type of sacral fracture (Denis) were examined for a correlation with the lumbosacral plexus palsy. Using coronal reconstruction CT, we considered a 10 mm or greater displacement at the sacrum or sacroiliac joint to be a longitudinal displacement. Transverse sacral fracture was diagnosed by sagittal reconstruction CT.

RESULTS

Of the 22 patients, 5 (22.7%) had lumbosacral plexus palsy (8 of 27 pelvic fractures) detected during treatment. The incidence of lumbosacral plexus palsy was not related to age, sex, ISS. Incidence of palsy was significantly higher when the patient's affected side had longitudinal displacement. Patients who had made a suicidal jump or had a sacral transverse fracture also had a significantly higher risk for lumbosacral plexus palsy. Palsy was not related to the type of pelvic fracture (AO) or sacral fracture (Denis).

CONCLUSION

In this study, longitudinal displacement of the pelvis, transverse sacral fracture, and trauma from a suicidal jump were risk factors for lumbosacral plexus palsy. These risk factors were helpful in our examination of patients who had severe pelvic fracture with loss of consciousness.

Complete traumatic anterior dislocation of the lumbosacral joint: a case report

STUDY DESIGN

A case report is presented.

OBJECTIVE

This report documents a case of complete traumatic anterior lumbosacral joint dislocation with the sacralization of L5.

SUMMARY OF BACKGROUND DATA

Traumatic anterior dislocation of the lumbosacral joint is a rare spondylolisthesis. The strategy for surgical treatment of traumatic dislocation of the lumbosacral joint remains controversial.

METHODS

A case of a 29-year-old man sustaining complete traumatic lumbosacral joint dislocation with the sacralization of L5 was treated successfully. Indirect radiologic signs such as bilateral multiple transverse process fractures were strongly suggestive of the diagnosis, which was further confirmed by 3-dimensional-computed tomography scan. This complete spondylolisthesis induced the instabilities of the entire soft tissues and caused severe cauda equina syndrome. The patient underwent an open reduction, decompression, and posterior fixation. Bilateral disrupted nerve roots were partly repaired simultaneously.

RESULTS

The patient successfully underwent surgery. An anatomically aligned and preserved solid spinal fusion was obtained during a 17-month follow-up. The patient had neurologic improvement in hip extension and knee flexion, and also could walk with an ankle brace.

CONCLUSION

Posterior instrumentation with the rod and screw system is considered a useful method for the management of complete traumatic anterior lumbosacral joint dislocation. However, prognosis is correlated with the initial neurologic status and the severity of other associated injuries.

Intradural repair of lumbar nerve roots for traumatic paraparesis leading to functional recovery

STUDY DESIGN

Case report and a literature review of intradural nerve graft repair of traumatic lacerations of lumbar nerve roots.

OBJECTIVE

Describe the technique and results of recent approach to the surgical management of traumatic lumbar nerve root injuries.

SUMMARY OF BACKGROUND DATA

Lumbar nerve root injuries are associated with a poor prognosis in terms of neurologic recovery and are generally managed conservatively. Animal studies and previous attempts at nerve root repair at both the level of the cervical and lumbar spine have demonstrated that some neurologic recovery is possible with the use of such methods.

METHODS

The management of a 29-year-old man who sustained a traumatic fracture of his second lumbar vertebra resulting in the lacerations of his right second and third lumbar nerve roots with associated neurologic deficits is presented. The technique of nerve root repair is described with the outcome assessed by means of clinical examination, magnetic resonance imaging, and electromyography.

RESULTS

At 8 years' clinical examination showed an absence of power in extension of his right knee with a complete recovery of motor function in hip flexion on the right side. Electromyography confirmed the clinical findings by demonstrating reinnervation of the right iliopsoas muscle.

CONCLUSIONS

This case describes a surgical approach to the management of traumatic lumbar nerve root injuries that offers the possibility of neurologic recovery and challenges the traditional approach of conservative management.

The paraspinal splitting approach: a possible approach to perform multiple intercosto-lumbar neurotizations: an anatomic study

STUDY DESIGN

Descriptive anatomy. OBJECTIVE.: To describe the anatomy associated with the extensive transmuscular paraspinal approach required to perform multiple intercosto-lumbar neurotizations.

SUMMARY OF BACKGROUND DATA

Neurotization of lumbar roots using lower intercostal nerves is a potential method of treating neurologic deficits after spinal cord injury. It appeared to us that the paraspinal splitting approach was potentially an optimal method to perform intercostal nerve harvesting, rerouting, and intercosto-lumbar neurotizations.

METHODS

Ninth, 10th, and 11th intercostal nerve harvesting and rerouting down to L2, L3, and L4 roots were performed on 50 cadavers. The descriptive anatomy and topographic landmarks are reported.

RESULTS

The mean total length of intercostal nerve harvested was 17.96 (range, 10-27) cm for the 9th intercostal nerve, 17.14 cm (range, 10-20) for the 10th intercostal nerve and 15.94 cm (range, 10-25) for the 11th intercostal nerve. The length of harvested nerve was not correlated to the size of the trunk. The length of harvested nerve was sufficient to perform lumbar roots neurotizations in the 300 cases of nerve harvesting.

CONCLUSION

Multiple lumbar roots neurotizations with lower intercostal nerves already have been proposed by other authors. In this strategy, the use of the spinal cord and intercostal nerves above the spinal cord lesion avoids the axonal regrowth required via the injured central nervous system. Rerouting intercostals nerves down to the lumbar roots at their exit from the intervertebral foraminae is less invasive that the same procedure performed down to the vertebral canal at the level of the cauda equina as we used in previous protocols. Our anatomic study confirms the advantage of the paraspinal sacrospinalis splitting approach in multiple intercosto-lumbar neurotizations. The approach is quick and easy and allows a good exposure of the nerve roots at the thoracic and lumbar levels. The L2, L3, and L4 roots could be satisfactorily neurotized with this procedure.

Lumbosacral plexus lesions

BACKGROUND

Aim of the present study was to analyse the main causes of lumbosacral plexus lesions together with the best diagnostic and therapeutic options for better patient outcome.

METHODS

We report our surgical experience with eight patients in whom lesion mechanisms consisted of high-energy trauma (4 pts), firearm injuries (2 pts), spontaneous retroperitoneal haematoma in anticoagulant therapy (1 pt) and schwannoma (1 pt). The diagnosis was not straightforward and included clinical aspects, electrophysiological studies, magnetic resonance and CT myelography. Surgery was performed by lateral extraperitoneal approach for the lumbar plexus, transperitoneal approach on the midline to reach the sacral plexus, and neuronavigation was used in the schwannoma case.

CONCLUSIONS

Lumbosacral plexus lesions require a challenging multidisciplinary approach to diagnose and treat; the outcome, even if delayed, was very encouraging. In all our patients pain was controlled, and six patients returned to unaided walking.

Anatomical feasibility of using the ninth, 10th, and 11th intercostal nerves for the treatment of neurological deficits after damage to the spinal cord

Object

The topographic anatomy of the lower intercostal nerves is less well known than that of the upper ones, except for the 12th intercostal nerve. It is possible to use the lower intercostal nerves to perform a neurotization of the lumbar roots. The authors studied the anatomy of the ninth, 10th, and 11th intercostal nerves to obtain descriptive and topographic anatomical data to aid in establishing optimal conditions for harvesting.

Methods

The ninth, 10th, and 11th intercostal nerves of 50 cadavers were dissected. The proximal part of the nerve in the posterior intercostal space (ISC) was exposed through a posterior approach. The lateral ICS was exposed through a lateral approach, under the latissimus dorsi, which made it possible to harvest the intercostal nerves using a stripping technique. A histological study was conducted on 10 pigs to evaluate the risk of nerve lesions during the stripping procedure.

Conclusions

The proximal course of the nerve in the posterior ICS was the same in all cases. The mean total length of the intercostal nerves harvested was 17.96 cm for the ninth, 17.14 cm for the 10th, and 15.94 cm for the 11th intercostal nerve. The harvested nerve length was sufficient in 297 of the 300 cases to perform lumbar root neurotization. The histological study showed no difference between the “open” and the “stripping” techniques regarding the risk of histological lesions in harvested nerves.

Novel repair strategies to restore bladder function following cauda equina/conus medullaris injuries

Trauma to the thoracolumbar junction or lumbosacral spine may result in a conus medullaris or cauda equina syndrome. In both conditions, symptoms typically include paraparesis or paraplegia, sensory impairment, pain, as well as bladder, bowel, and sexual dysfunctions. We present in this review a series of neural repair strategies that have been developed to address the unique features and challenges of subjects with a conus medullaris or cauda equina syndrome. We address, in particular, neural repair strategies that may have a translational research potential to restore bladder function. Recent animal injury models have suggested that a progressive retrograde death of both autonomic and motor neurons may contribute to the neurological deficits in subjects with conus medullaris and cauda equina injuries. For subjects with acute injuries, we present novel strategies to promote neuroprotection, axonal regeneration, and functional reinnervation of the lower urinary tract. For subjects with chronic injuries, we discuss new approaches to replace lost autonomic and motor neurons. A brief discussion on a variety of outcome measures that may be suitable to evaluate the function of the lower urinary tract in rodent neural repair models is also provided.

Glial reactions in a rodent cauda equina injury and repair model

In the adult rat, an avulsion injury of lumbosacral ventral roots results in a progressive and pronounced loss of the axotomized motoneurons. A subsequent acute implantation of an avulsed ventral root into the spinal cord has neuroprotective effects. However, it has not been known whether a surgical implantation of an avulsed ventral root into the spinal cord for neural repair purposes affects intramedullary glial and microglial reactions. Here, adult female Sprague-Dawley rats underwent a unilateral L5-S2 ventral root avulsion injury with or without acute implantation of the L6 ventral root into the spinal cord. At 4 weeks postoperatively, immunohistochemistry using primary antibodies to GFAP (astrocytes), Ox-42 (microglia), and ED-1 (macrophages) was performed at the L6 spinal cord segment, and quantified using densitometry. Our results show that a lumbosacral ventral root avulsion injury induces an activation of astrocytes, microglia, and macrophages in the ventral horn. Interestingly, an acute implantation of an avulsed root into the white matter does not significantly affect the activation of glial cells or macrophages in the ventral horn. We speculate that neuroprotective and axonal growth promoting benefits of the combined glial and microglial/ macrophage responses may outweigh their potential negative effects, as previous studies have shown that implantation of avulsed roots is a successful strategy in promoting reinnervation of peripheral targets.

Complement activation after lumbosacral ventral root avulsion injury

A lumbosacral ventral root avulsion (VRA) injury results in a pronounced loss of motoneurons, in part due to apoptosis. Caspase inhibitors may rescue motoneurons after a VRA in neonatal rats, but this treatment approach has been unsuccessful to protect motoneurons subjected to the same injury in adult rats. Other mechanisms may contribute to the retrograde motoneuron death encountered in adult animals. Here, we study whether the complement system, a part of the innate immune system, contributes to motoneuron death after a lumbosacral VRA. Adult Sprague-Dawley rats underwent a unilateral L5-S2 VRA injury. At 10 days postoperatively, quantitative immunohistochemical studies demonstrated that the lytic membrane attack complex (MAC) targeted approximately 38% of axotomized motoneurons. The MAC inhibitor Clusterin was concurrently expressed at significantly higher levels in astrocytes and de novo in 30% of the remaining motoneurons. Our data suggest that complement activation and necrosis contribute to motoneuron death after lumbosacral VRA injuries. We speculate that inhibition of MAC may constitute a potential neuroprotective strategy following cauda equina injuries.

Multiple lumbar plexus neurotizations of the ninth, tenth, and eleventh intercostal nerves

The topographic anatomy of the lower intercostal nerves is less known than the upper ones except for the twelfth intercostal nerve. It is possible to use the lower intercostal nerves to carry out a neurotization of the lumbar roots. We studied the anatomy of the ninth, tenth, and eleventh intercostal nerves in order to specify the data of descriptive and topographic anatomy allowing to carry out their harvesting under good conditions. Ninth, tenth, and eleventh intercostal nerves of 50 cadavers were dissected. The proximal part of the nerve in the posterior intercostal space was exposed through a posterior approach. The lateral intercostal space was exposed through a lateral approach, under the latissimus dorsi, which made it possible to harvest the intercostals nerve. The proximal course of the nerve in posterior intercostals space was the same in all the cases. The nerve moves obliquely towards the outside to reach the lower border of the rib. The exit of posterior intercostal space is a fibrous strait that marks the entry of a channel between two muscular layers. We describe an aponevrotic channel in which the nerve and the vessels are, immediately at the lower border of the cranial rib. The mean total length of intercostal nerve harvested by our technique was 17.96 cm for the ninth intercostal nerve, 17.14 cm for the tenth intercostal nerve, and 15.94 cm for the eleventh intercostal nerve. The bifurcation of the intercostal nerve in a deep branch and the ramus cutaneus lateralis was found in the majority of the cases, from 9.5 to 21 cm of the emergence of the intercostal nerve in posterior intercostal space. This anatomical study of the ninth, tenth, and eleventh intercostal nerves in posterior intercostal space and lateral intercostal space appears to us to allow the realization of a reliable surgical harvesting.