Use of clinical signs and computed tomography myelography findings in detecting and excluding nerve root avulsion in complete brachial plexus palsy

Diagnostic Ability of Ultrasonography in Brachial Plexus Root Injury at Different Stages Post-trauma

Brachial plexus (BP) root injury often results in disability of the upper extremities. Improvements in high-frequency ultrasonography have enabled the visualization of BP nerve roots. This study was aimed at quantifying the diagnostic accuracy of ultrasonography in BP root injury at different stages post-trauma. A consecutive series of 170 patients with BP root injury between 2015 and 2019 were studied retrospectively and divided into three groups on the basis of time between injury and ultrasound examination (≤1 mo, 1-3 mo, >3 mo). Diagnosis of complete BP root injury under ultrasound was determined using a pre-defined criterion, including pseudomeningocele, retraction and rupture. Diagnostic accuracy was calculated based on surgical findings and intra-operative electrophysiological tests. Rates of detection of the cervical (C5-C8) and thoracic (T1) nerve roots under ultrasound were 99.4%, 99.4%, 99.4%, 95.9% and 79.4%, respectively. The sensitivity for complete BP root injury was 0.74, and the specificity was 0.91. No significant differences in sensitivity or specificity were observed across time stages. Ultrasound exhibited substantial consistency with surgical findings (κ = 0.70) for complete BP root injury at any stage post-injury. Ultrasound can be an optional method of diagnosis of complete BP root injury at an early stage post-injury.

Two clinical tests assessing long thoracic nerve function to determine C5 and C6 root graft eligibility in patients with brachial plexus injury

OBJECTIVE

Identifying roots available for grafting is of paramount importance prior to reconstructing complex injuries involving the brachial plexus. This is traditionally achieved by combining input from both clinical examinations and imaging studies. In this paper, the authors describe and evaluate two new clinical tests to study long thoracic nerve function and, consequently, to predict the status of the C5 and C6 roots after global brachial plexus injuries.

METHODS

From March 2020 to December 2020, in 41 patients undergoing brachial plexus repair, preoperative clinical assessments were performed using modified C5 and C6 protraction tests, C5 and C6 Tinel's signs, and MRI findings to predict whether graft-eligible C5 and C6 roots would be identified intraoperatively. Findings from these three assessments were then combined in a logistic regression model to predict graft eligibility, with overall predictive accuracies calculated as areas under receiver operating characteristic curves.

RESULTS

In the 41 patients, the pretest probability of C5 root availability for grafting was 85% but increased to 92% with a positive C5 protraction test and to 100% when that finding was combined with a positive C5 Tinel's sign and favorable MRI findings. The pretest probability of C6 root availability was 40%, which increased to 84% after a positive C6 protraction test and to 93% when the protraction test result concurred with Tinel's test and MRI findings.

CONCLUSIONS

Combining observations of the protraction tests with Tinel's sign and MRI findings accurately predicts C5 and C6 root graft eligibility.

Team Approach: Management of Brachial Plexus Injuries

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Traumatic brachial plexus injuries are relatively rare but potentially devastating injuries with substantial functional, psychological, and economic consequences.

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Prompt referral (ideally within 6 weeks of injury) to a center with a team of experts experienced in the diagnosis and management of these injuries is helpful to achieving optimal outcomes.

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Preoperative and intraoperative decision-making to diagnose and plan reconstructive procedures is complex and must take into account a number of factors, including the time from injury, concomitant injuries, preservation of cervical nerve roots, and the availability of intraplexal and extraplexal donor nerves for nerve transfer.

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A team approach is essential to ensure accurate localization of the pathology before surgery and to maximize rehabilitation after surgery, necessitating close contact between the surgical team, physiatrists, radiologists, and therapists.

Respiratory failure due to diaphragm paralysis after brachial plexus injury diagnosed by point-of-care ultrasound

A man in his fifties was injured in a traffic accident and diagnosed with traumatic subarachnoid haemorrhage, liver injury, and fractures of the rib, right clavicle, right scapula and right femur. He also presented with motor and sensory disturbances of the right upper extremity and was suspected of having a brachial plexus injury. After undergoing mechanical ventilation due to multiple traumas, he was extubated. However, he developed acute respiratory failure and required reintubation. Respiratory symptoms were not clear until just before reintubation. The diagnosis of right diaphragm paralysis was made using point-of-care ultrasound with no other findings that could cause respiratory failure. MRI led to the diagnosis of brachial plexus injury, which likely caused diaphragm paralysis. Point-of-care ultrasound provided a clear visualisation and rapid bedside diagnosis of diaphragm paralysis, which can be challenging to diagnose while ruling out other causes of respiratory failure.

Predicting Healthy C5 Spinal Nerve Stumps Eligible for Grafting with MRI, Tinel Test, and Rhomboid Electromyography: A Retrospective Study of 295 Consecutive Brachial Plexus Surgeries

Background MRI, Tinel test, and rhomboid electromyography (EMG) can be used to predict whether C5 spinal nerve stumps are healthy and eligible for grafting in acute adult brachial plexus injuries, but their comparative diagnostic efficacies have not been evaluated. Purpose To compare diagnostic performances of MRI, Tinel test, and rhomboid EMG in predicting healthy C5 spinal nerve stumps that are eligible for grafting. Materials and Methods This retrospective study included consecutive adult patients with acute brachial plexus injury who underwent microreconstructions between January 2008 and December 2018. Healthy C5 spinal nerve stumps eligible for grafting with preceding normal intradural nerve rootlets were diagnosed by an experienced neuroradiologist using an avulsion severity score system based on fast imaging employing steady-state acquisition or FIESTA neurography, which separates intradural nerve rootlets into normal, partial mild, severe, and complete avulsions. Tinel test and rhomboid EMG results were assessed by an experienced nerve surgeon and neurologist, respectively. The accuracy, sensitivity, and specificity of the three tests were compared using microdissection as the reference standard. P < .05 was considered to indicate a significant difference. Results A total of 251 patients (mean age, 31 years ± 13 [standard deviation]; 217 men) with brachial plexus injuries who had -undergone MRI (n = 251), Tinel test (n = 235), rhomboid EMG (n = 181) and MRI, Tinel test, and EMG (n = 172) were -included. Accuracy, sensitivity, and specificity, respectively, in predicting healthy C5 spinal nerve stumps eligible for grafting were 93% (233 of 251), 84% (58 of 69), and 96% (175 of 182) for MRI; 59% (139 of 235), 56% (37 of 66), and 60% (102 of 169) for Tinel test; and 39% (71 of 181), 85% (43 of 50), and 21% (28 of 131) for rhomboid EMG. MRI (area under the receiver operating characteristic curve [AUC], 0.90; P < .001) -outperformed MRI and Tinel test (AUC, 0.74), Tinel test (AUC, 0.59), and rhomboid EMG (AUC, 0.53). Conclusion MRI performed best in the prediction of healthy graftable C5 spinal nerve stumps in acute adult brachial plexus injuries. © RSNA, 2021 Online supplemental material is available for this article.

Relocating the C5 nerve stump in C5 nerve grafting to prevent iatrogenic phrenic nerve injury

BACKGROUND

Exploration and grafting of the brachial plexus remains the gold standard for post-ganglionic brachial plexus injuries that present within an acceptable time frame from injury. The most common nerves available for grafting include C5 and C6. During the surgical exposure of C5 and C6, the phrenic nerve is anatomically anterior to the cervical spinal nerves, making it vulnerable to injury while performing the dissection and nerve stump to graft coaptation. We describe a novel technique that protects the phrenic nerve from injury during supraclavicular brachial plexus exposure and grafting of C5 or upper trunk ruptures or neuromas in-continuity.

METHODS

A 4-step technique is illustrated: (1) The normal anatomic relationships of the phrenic nerve anterior to C5 is displayed in the face of the traumatic scarring. (2) The C5 spinal nerve stump is then transposed from its anatomic position posterior to the phrenic nerve to an anterior position. (3) The C5 stump is then moved medially for retrograde neurolysis of C5 from its phrenic nerve contribution. The graft coaptation to C5 is performed in this medial position, which minimizes retraction of the phrenic nerve. (4) The normal anatomic relationship of the phrenic nerve and the C5 nerve graft is restored.

RESULTS

We have been routinely relocating the C5 spinal nerve stump around the phrenic nerve for the past 10 years. We have experienced no adverse respiratory events.

CONCLUSION

This technique facilitates surgical exposure and prevents iatrogenic injury on the phrenic nerve during nerve reconstruction.

Comparison of Different In Vivo Animal Models of Brachial Plexus Avulsion and Its Application in Pain Study

Brachial plexus injuries (BPIs) are high-energy trauma that can result in serious functional problems in the affected upper extremities, and brachial plexus avulsion (BPA) could be considered the most severe type of them. The booming occurrence rate of BPA brings up devastating impact on patients' life. Complications of muscle atrophy, neuropathic pain, and denervation-associated psychological disorders are major challenges in the treatment of BPA. Animal models of BPA are good vehicles for this kind of research. Full understanding of the current in vivo BPA models, which could be classified into anterior approach avulsion, posterior approach avulsion, and closed approach avulsion groups, could help researchers select the appropriate type of models for their studies. Each group of the BPA model has its distinct merits and demerits. An ideal BPA model that can inherit the advantages and make up for the disadvantages is still required for further exploration.

Approach to the Pan-brachial Plexus Injury: Variation in Surgical Strategies among Surgeons

Treatment of pan-brachial plexus injuries has evolved significantly over the past 2 decades, with refinement and introduction of new surgical techniques, particularly free functional muscle transfer. The extent to which contemporary brachial plexus surgeons utilize various techniques as part of their treatment algorithm for pan-plexus injuries and the rationale underlying these choices remain largely unknown.

Methods

A case scenario was posed to 12 brachial plexus surgeons during semi-structured qualitative interviews. The case involved a young patient presenting 6 weeks after a pan-plexus injury from a motorcycle accident. Surgeons were asked to formulate a treatment plan. Inductive thematic analysis was used to identify commonalities and variation in approach to treatment.

Results

For shoulder function, the majority of surgeons would graft from a viable C5 nerve root, if possible, though the chosen target varied. Two-thirds of the surgeons would address elbow flexion with nerve transfers, though half would combine this with a free functional muscle transfer to increase elbow flexion strength. Free functional muscle transfer was the technique of choice to restore finger flexion. Finger extension, intrinsic function, and sensation were not prioritized.

Conclusions

Our study sheds light on current trends in the approach to pan-plexus injuries in the U.S. and identifies areas of variability that would benefit from future study. The optimal shoulder target and the role for grafting to the MCN for elbow flexion merit further investigation. The role of FFMT plays an increasingly prominent role in treatment algorithms.

Surgical reconstructions for adult brachial plexus injuries. Part I: Treatments for combined C5 and C6 injuries, with or without C7 injuries

Brachial plexus injuries will cause a significantly decreased quality of life. Patients with upper arm type brachial plexus injuries, which means C5 and C6 roots injury, will lose their shoulder elevation/abduction/external rotation, and elbow flexion function. Additional elbow, wrist, and hand extension function deficit will occur in patients with C7 root injury. With the advances of reconstructive procedures, the upper arm brachial plexus injuries can be successfully restored through nerve repair, nerve grafting, nerve transfer, muscle / tendon transfer and free functioning muscle transfer. In this review article, we summarized the various reconstructive procedures to restore the function of shoulder and elbow. Nowadays, the upper arm type BPI can be treat with satisfied outcomes (80-90% successful rate).

Viable C5 and C6 Proximal Stump Use in Reconstructive Surgery of the Adult Brachial Plexus Traction Injuries

BACKGROUND

In patients with only upper (C5, C6) brachial plexus palsy (BPP), the pooled international data strongly favor nerve transfers over nerve grafts. In patients with complete BPP, some authors favor nerve grafts for the restoration of priority functions whenever there is a viable proximal stump.

OBJECTIVE

To evaluate functional recovery in cases of upper and complete BPP where only direct graft repair from viable proximal stumps was performed.

METHODS

The study included 36 patients (24 with complete BPP and 12 with only upper BPP) operated on over a 15-yr period. In all cases, direct graft repair from C5 to the musculocutaneous and the axillary nerve was performed. In cases with complete BPP, additional procedures included either direct graft repair from C6 to the radial nerve and the medial pectoral nerve or the dorsal scapular nerve transfer to the branch for the long head of the triceps.

RESULTS

The use of C5 proximal stump grafts (in both complete and upper BPP) resulted in satisfactory elbow flexion in 26 patients (72.2%) and satisfactory shoulder abduction in 22 patients (61.1%). The use of C6 proximal stump grafts in patients with complete BPP resulted in satisfactory elbow extension in 5 (50%) and satisfactory shoulder adduction in another 5 (50%) patients.

CONCLUSION

Although nerve transfers generally enable better restoration of priority functions, in cases of infraganglionary injuries, especially in shorter defects, it is also necessary to consider direct graft repair, or at least its combination with nerve transfers, as a potentially beneficial treatment modality.

ACR Appropriateness Criteria® Plexopathy

MRI without and with contrast is the most accurate imaging method to determine whether a process is intrinsic or extrinsic to a nerve of the brachial or lumbosacral plexus. However, there are no Current Procedural Terminology codes to correspond to imaging studies of the brachial or lumbar plexus discretely. This assessment uses "MRI of the brachial plexus" or "MRI of the lumbosacral plexus" as independent entities given that imaging acquisition for the respective plexus differs in sequences and planes compared with those of a routine neck, chest, spine, or pelvic MRI, yet acknowledges the potential variability of ordering practices across institutions. In patients unable to undergo MRI, CT offers the next highest level of anatomic evaluation. In oncologic patients, PET/CT imaging can identify the extent of tumor involvement and be beneficial to differentiate radiation plexitis from tumor recurrence but provides limited resolution of the plexus itself. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Patterns of Brachial Plexus Stretch Palsy in a Prospective Series of 565 Surgically Treated Patients

PURPOSE

To report the distribution of the different patterns of stretch brachial plexus injuries (BPIs) in a retrospective cohort of patients operated at our institution during an 11-year period.

METHODS

From September 2002 to June 2012, we evaluated and operated on 565 patients with traction injuries of the brachial plexus. Average age was 26.8 years (SD ±9.3 years); the interval between the injury and surgery was 5.4 months (SD ±2.8 months). The pattern of injury was defined based on data obtained from a standardized clinical examination, preoperative helical computed tomography myelography after intradural contrast injection, surgical findings, and intraoperative electric stimulation.

RESULTS

Supraclavicular injuries accounted for 91% of all cases (N = 512) whereas 9% of injuries were infraclavicular. Within the supraclavicular injuries, 50% of cases involved the entire plexus and in 12% there was avulsion of all 5 roots. Among them, 94% involved the upper plexus (C5 to C6 ± C7 ± C8), and 6% the lower plexus (C8 to T1 ± C7). C5 to C6 injuries accounted for 23% of partial BPI, C5 to C7 19%, C5 to C8 52%, C7 to T1 4%, and C8 to T1 2%.

CONCLUSIONS

The most relevant findings of this study were that most panplexal BPIs showed at least one graftable root, there was a high prevalence of C5 to C8 BPI, C7 to T1 root injury was the most common pattern of lower type of injury, and infraclavicular BPI was uncommon.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic IV.

A new rat model of neuropathic pain: complete brachial plexus avulsion

Brachial plexus avulsion (BPA) is one of the major injuries in motor vehicle accidents and may result in neuropathic pain. Accumulating evidence suggests that 30-80% of BPA developed neuropathic pain in human. In our study, complete brachial plexus avulsion (C5-T1) rats model leads to the results that 37.5% of rats had long-lasting (up to 6 months) mechanical allodynia and cold allodynia. We observed the activation of astrocyte and microglial in cervical spinal cord after BPA. Complete brachial plexus avulsion mimics human nerve root traction injury following traffic accidents. The complete BPA rat model approach human injuries and can be used for further investigations.

The diagnostic value of CT myelography, MR myelography, and both in neonatal brachial plexus palsy

BACKGROUND AND PURPOSE

Although most infants with brachial plexus palsy recover function spontaneously, approximately 10-30% benefit from surgical treatment. Pre-operative screening for nerve root avulsions is helpful in planning reconstruction. Our aim was to compare the diagnostic value of CT myelography, MR myelography, and both against a surgical criterion standard for detection of complete nerve root avulsions in birth brachial plexus palsy.

MATERIALS AND METHODS

Nineteen patients who underwent a preoperative CT and/or MR myelography and subsequent brachial plexus exploration were included. Imaging studies were analyzed for the presence of abnormalities potentially predictive of nerve root avulsion. Findings of nerve root avulsion on surgical exploration were used as the criterion standard to assess the predictive value of imaging findings.

RESULTS

Ninety-five root levels were examined. When the presence of any pseudomeningocele was used as a predictor, the sensitivity was 0.73 for CT and 0.68 for MR imaging and the specificity was 0.96 for CT and 0.97 for MR imaging. When presence of pseudomeningocele with absent rootlets was used as the predictor, the sensitivity was 0.68 for CT and 0.68 for MR imaging and the specificity was 0.96 for CT and 0.97 for MR imaging. The use of both CT and MR imaging did not increase diagnostic accuracy. Rootlet findings in the absence of pseudomeningocele were not helpful in predicting complete nerve root avulsion.

CONCLUSIONS

Findings of CT and MR myelography were highly correlated. Given the advantages of MR myelography, it is now the single technique for preoperative evaluation of nerve root avulsion at our institution.

The C5 root dermatome enlarges and modulates hand pain in total brachial plexus palsy

Hand pain is a major complaint in 80% of the patients with complete brachial plexus palsy; and, in 80% of these patients, the C5 root is ruptured and the C6-T1 roots avulsed from the spinal cord. It has been suggested that pain in brachial plexus injuries may not arise from avulsed roots, but rather from ruptured roots. Traditionally the C5 root dermatome does not extend to the hand. We have hypothesized that in total lesions of the brachial plexus the C5 root dermatome expands, reaching the hand. In 20 patients with confirmed C5 root rupture and C6-T1 root avulsion, we investigated the distribution of C5 root paresthesia six to eight weeks after grafting. After cervical percussion in search of Tinel’s sign, maps related to reported paresthesia were drawn on the affected limb. We observed that paresthesia following C5 root percussion reached the hands and fingers, dermatomes linked to the C6 and C8 roots. Immediately after percussion, for a few seconds, 14 patients who complained of pain during examination reported the augmentation of numbness and pain resolution. After brachial plexus injury, the C5 root dermatome expands and modulates hand pain.

Activation of astrocytes and microglia in the C3-T4 dorsal horn by lower trunk avulsion in a rat model of neuropathic pain

PURPOSE

Brachial plexus pain is thought to be generated not by avulsed roots but rather by nonavulsed roots, because avulsed roots could not transmit action potentials to central nerves. The aim of this study was to evaluate pain-related behavior and the extent of glial activation in a model of brachial plexus avulsion (BPA).

METHODS

We used 24 male Wistar rats. For rats in the BPA group, the C8-T1 roots were avulsed from the spinal cord at the level of the lower trunk (n = 10). Rats in a sham-surgery group had a similar surgery without the root avulsion (n = 7). Rats in an untreated group had no surgery (n = 7). Mechanical hyperalgesia of the forelimb plantar surfaces corresponding to C6 and C7 dermatomes was evaluated using a Semmes-Weinstein monofilament test every third day for 3 weeks (n = 15). Activation of astrocytes and microglia was examined immunohistochemically using anti-glia fibrillary acidic protein and anti-Iba1 antibodies 3 days after surgery (n = 9).

RESULTS

When compared with rats in the sham-surgery and naive control groups, rats in the BPA group displayed significant mechanical hyperalgesia in the dermatome innervated by uninjured nerves both ipsilaterally and contralaterally and continuing through day 21. Iba1-immunoreactive microglia and glia fibrillary acidic protein-immunoreactive astrocytes were significantly activated on the ipsilateral side in the BPA group from levels C3 to T3 compared with the sham-surgery and untreated groups of rats.

CONCLUSIONS

Activation of glia at uninjured levels of the dorsal horn may facilitate pain transmission following BPA injury. Consequently, spared spinal glial cells may represent therapeutic targets for treatment of pain related to BPA injury.

CLINICAL RELEVANCE

Our findings may indicate why neuropathic pain is so frequent and intense following BPA injury.

Grafting the C5 Root to the Musculocutaneous Nerve Partially Restores Hand Sensation in Complete Palsies of the Brachial Plexus

BACKGROUND:

In complete brachial plexus palsy, we have hypothesized that grafting to the musculocutaneous nerve should restore some hand sensation because the musculocutaneous nerve can drive hand sensation directly or via communication with the radial and median nerves.

OBJECTIVE:

To investigate sensory recovery in the hand and forearm after C5 root grafting to the musculocutaneous nerve in patients with a total brachial plexus injury.

METHODS:

Eleven patients who had recovered elbow flexion after musculocutaneous nerve grafting from a preserved C5 root and who had been followed for a minimum of 3 years were screened for sensory recovery in the hand and forearm. Six matched patients who had not undergone surgery served as controls. Methods of assessment included testing for pain sensation using Adson forceps, cutaneous pressure threshold measurements using Semmes-Weinstein monofilaments, and the static 2-point discrimination test. Deep sensation was evaluated by squeezing the first web space, and thermal sensation was assessed using warm and cold water.

RESULTS:

All grafted patients recovered sensation in a variable territory extending from just over the thenar eminence to the entire lateral forearm and hand. Seven patients were capable of perceiving 2-0 monofilament pressure on the thenar eminence, palm, and dorsoradial aspect of the hand. All could differentiate warm and cold water. None recovered 2-point discrimination. None of the patients in the control group recovered any kind of sensation in the affected limb.

CONCLUSION:

Grafting the musculocutaneous nerve can restore nociceptive sensation on the radial side of the hand.

Use of long autologous nerve grafts in brachial plexus reconstruction: factors that affect the outcome

BACKGROUND

Using grafts directed to distal targets in brachial plexus reconstruction has the advantage over proximal targets of avoiding axonal dispersion. A long graft (more than 10 cm) is needed to reach most distal targets. The objective of this article is to identify factors associated with good versus poor outcomes in a clinical series of long grafts used for distal brachial plexus reconstruction.

METHODS

In 34 patients with a flail arm, 47 sural grafts >10 cm long were followed for ≥2 years postoperatively. Surgical technique included standard supraclavicular exposure of the proximal brachial plexus and its branches, the phrenic nerve and spinal accessory nerve. Distal target nerves were exposed via an incision starting at the axilla, following the gap between the biceps and triceps. Cases achieving a good result were statistically compared against those with a poor result as to the donor nerve/root, target nerve, patient age and weight, time from trauma to surgery, graft length and long-term rehabilitation quality.

FINDINGS

A good outcome was observed with 23 grafts (48.9%), but 66.7% of the 30 long grafts done within 6 months of trauma yielded a good result. Only 1 of 15 patients with the lowest quality rehabilitation score experienced a good result (6.6%) versus all 12 patients with the highest rating (p < 0.001). Trauma-to-surgery time was roughly half as long in those with a good result (4.7 vs. 9.0 months, p < 0.001). No other inter-group differences were observed.

CONCLUSIONS

The results of a series of distal brachial plexus target reinnervations with long grafts is presented and analyzed. According to them, time from trauma to surgery and an adequate postoperative rehabilitation are important predictors of outcome.

Results and current approach for Brachial Plexus reconstruction

We review our experience treating 335 adult patients with supraclavicular brachial plexus injuries over a 7-year period at the University of Southern Santa Catarina, in Brazil. Patients were categorized into 8 groups, according to functional deficits and roots injured: C5-C6, C5-C7, C5-C8 (T1 Hand), C5-T1 (T2 Hand), C8-T1, C7-T1, C6-T1, and total palsy. To restore function, nerve grafts, nerve transfers, and tendon and muscle transfers were employed. Patients with either upper- or lower-type partial injuries experienced considerable functional return. In total palsies, if a root was available for grafting, 90% of patients had elbow flexion restored, whereas this rate dropped to 50% if no roots were grafted and only nerve transfers performed. Pain resolution should be the first priority, and root exploration and grafting helped to decrease or eliminate pain complaints within a short time of surgery.

Undeveloped semiconic posterosuperior ligament and susceptibility to avulsion of the C-7 spinal nerve in Erb palsy

OBJECT

In Erb palsy, the C-7 spinal nerve has been found to be more subject to avulsion than the C-5 and C-6 spinal nerves. This study investigated the morphological and biomechanical characteristics of the semiconic posterosuperior ligaments (SPLs) at the C-5, C-6, and C-7 spinal nerves in neonates.

METHODS

Twenty-four brachial plexuses from 12 fresh neonate cadavers were used in this study. In 12 brachial plexuses from 6 cadavers, the following studies were performed with respect to the SPLs at the C-5, C-6, and C-7 spinal nerves: gross observation of morphological and histological characteristics; measurement of length, thickness, and width; and a semiquantitative analysis of collagen. In the other 6 cadavers, biomechanical tension testing was performed bilaterally on the C5-7 SPLs to assess the tensile strength of the ligaments.

RESULTS

The C5-7 spinal nerves are fixed to the transverse process through the SPL, a structure not observed at the C-8 and T-1 spinal nerves. Except for the width of the SPL insertion on the spinal nerve, which was found to increase gradually from C-5 to C-7, there was no statistically significant difference in the dimensions of the C-5, C-6, and C-7 SPLs. The sectional area percentage of collagen was 51% ± 10% in SPLs for C-5, 51% ± 11% for C-6, and 41% ± 10% for C-7; and this percentage was significantly lower in SPLs for C-7 than for C-5 or C-6 (1-way ANOVA, F = 4.3, p = 0.02; Tukey honestly significant difference test, p = 0.04 and 0.04, respectively). Sharpey fibers were observed at the transverse process origin of the SPL at C-5 and C-6 but not at C-7. Biomechanical tension testing showed that the mean failure load was 6.6 ± 0.9 N for the C-5 SPL, 6.4 ± 1.0 N for the C-6 SPL, and 5.4 ± 0.9 N for the C-7 SPL, and the failure load was significantly lower in SPLs at C-7 than in those at C-5 or C-6 (1-way ANOVA, F = 5.1, p = 0.01; Tukey honestly significant difference, p = 0.01 and 0.048, respectively). Nine of 12 C-7 SPLs failed at their origin from the transverse process, while only 4 of 12 C-5 SPLs and 3 of 12 C-6 SPLs failed at the origin site.

CONCLUSIONS

These findings suggest that the lower density of collagen and absence of Sharpey fibers decrease the biomechanical properties of the C-7 SPL, and this may account for the higher frequency of avulsion of the C-7 spinal nerve (in comparison with the C-5 or C-6 nerve) in Erb palsy.

Transfer of the Platysma Motor Branch to the Accessory Nerve in a Patient With Trapezius Muscle Palsy and Total Avulsion of the Brachial Plexus

BACKGROUND AND IMPORTANCE:

To report on the successful use of a platysma motor nerve transfer to the accessory nerve in a patient with concomitant trapezius and brachial plexus palsy.

CLINICAL PRESENTATION:

A 20-year-old man presented with total avulsion of the right brachial plexus combined with palsies of the accessory and phrenic nerve. The patient was operated on 4 months after his injury. The accessory nerve was repaired via direct transfer of the platysma motor branch. The contralateral C7 root was connected to the musculocutaneous nerve, and the hemihypoglossal nerve was grafted to the suprascapular nerve. Two intercostal nerves were attached to the triceps long head motor branch.

CONCLUSION:

Within 20 months of surgery, the patient regained full reinnervation of the upper trapezius muscle. Elbow flexion scored M3+, and 30° active shoulder abduction was observed. Triceps reinnervation was poor. Platysma motor branch transfer to the accessory nerve is a viable alternative to reinnervate the trapezius muscle.

Combined Injury of the Accessory Nerve and Brachial Plexus

BACKGROUND:

Stretch-induced spinal accessory nerve palsy has been considered extremely rare, with only a few cases reported.

OBJECTIVE:

In 357 patients with stretch lesions of the brachial plexus, we investigated the prevalence, course, and surgical treatment of accessory nerve palsy.

METHODS:

Accessory nerve palsy was ascertained when the patient was unable to shrug the ipsilateral shoulder. Patients underwent brachial plexus reconstruction between 6 and 8 months after trauma. To confirm paralysis, during surgery, the accessory nerve was stimulated electrically.

RESULTS:

Accessory nerve palsy occurred in 19 of the 327 patients (6%) with upper type or complete palsy of the brachial plexus. Proximal injuries of the accessory nerve accompanied by voice alteration and complete palsy of the sternocleidomastoid and trapezius muscle occurred in 2 patients. Proximal palsy without vocal alterations was observed in 6 patients. Palsy of the trapezius muscle with preservation of the sternocleidomastoid muscle occurred in 11 patients. All 7 patients who demonstrated muscle contractions upon electrical stimulation of the accessory nerve during surgery recovered completely. Patients with surgical reconstruction of the accessory nerve through grafting (n = 2) or repair by platysma motor nerve transfer (n = 2) recovered active shoulder shrugging within 36 months of surgery. Seven of the 8 patients without accessory nerve reconstruction recovered from their drop shoulder and head tilt, but remained unable to shrug.

CONCLUSION:

If intraoperative electrical stimulation produces contraction of the upper trapezius muscle, no repair is needed. In proximal injuries, the platysma motor branch should be transferred to the accessory nerve; whereas in paralysis distal to the sternocleidomastoid muscle, the accessory nerve should be explored and grafted.

Sensory disturbances and pain complaints after brachial plexus root injury: a prospective study involving 150 adult patients

After injury of the brachial plexus, sensory disturbance in the affected limb varies according to the extent of root involvement. The goal of this study was to match sensory assessments and pain complaints with findings on CT myelo scans and surgical observations. One hundred fifty patients with supraclavicular stretch injury of the brachial plexus were operated upon within an average of 5.4 months of trauma. Preoperatively, upper limb sensation was evaluated using Semmes-Weinstein monofilaments. Pain complaints were recorded for each patient. With lesions affecting the upper roots of the brachial plexus, hand sensation was largerly preserved. Sensory disturbances were identified over a longitudinal bundle on the lateral arm and forearm. In C8-T1 root injuries, diminished protective sensation was observed on the ulnar aspect of the hand. If the C7 root also was injured, sensation in the long finger was impaired. Eighty-four percent of our 64 patients with total palsy reported pain, versus just 47% of our 72 patients with upper type palsies. This rate dropped to 29% in the 14 patients with a lower-type palsy. C8 and T1, when injured, always were avulsed from the cord; when avulsion of these roots was the only nerve injury, pain was absent. Hand sensation was largely preserved in patients with partial injuries of the brachial plexus, particularly on the radial side. Even when T1 was the only preserved root, hand sensation was mostly spared. This indicates that overlapping of the dermatomal zones seems much more widespread than previously reported.

Reconstruction of complete palsies of the adult brachial plexus by root grafting using long grafts and nerve transfers to target nerves

PURPOSE

We report on the results we obtained with reconstruction for total paralysis of the brachial plexus using long nerve grafts that connect nonavulsed roots to the musculocutaneous and radial nerve. Nerve transfers were performed to restore function of the suprascapular nerve, triceps long head, and pectoralis major muscle.

METHODS

We studied 22 young adults with complete brachial plexus palsy who had surgical repair an average of 5 months after trauma. Nerve grafts connected the C5 root to the musculocutaneous nerve. The C6 root was connected by grafts to the radial nerve. When the C6 root was avulsed, the levator scapulae motor branch was connected by grafts to the triceps long head motor branch. In 13 patients, the platysma motor branch was transferred to the medial pectoralis nerve through a long nerve graft. The suprascapular nerve was repaired through transfer of the accessory nerve. Outcomes were assessed an average of 27 months after surgery, focusing on recovery of muscle strength, categorized using the Medical Research Council scale.

RESULTS

All but one patient recovered some shoulder abduction, with a mean range of recovered shoulder abduction of 57°. Pectoralis major reinnervation was observed in 9 of the 13. Twenty patients recovered full elbow flexion and achieved at least grade M3 strength. Among the 10 patients in whom the C6 root was grafted to the radial nerve, 4 patients recovered active elbow extension with biceps co-contraction. All patients in whom the levator scapulae nerve was connected to the triceps long head recovered active elbow extension, albeit weak. Double lesions of the musculocutaneous nerve were identified in 4 patients.

CONCLUSIONS

Accessory to suprascapular nerve transfer, levator scapulae nerve transfer to the triceps long head and C5 root grafting to the musculocutaneous nerve is now our preferred method of reconstruction in total palsies of the brachial plexus.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Results of grafting the anterior and posterior divisions of the upper trunk in complete palsies of the brachial plexus

PURPOSE

In most complete brachial plexus injuries, at least 1 root still is available for grafting. We report on the results obtained with reconstruction of the brachial plexus using short sural nerve grafts that connect nonavulsed roots to the anterior, posterior, or both divisions of the upper trunk.

METHODS

We prospectively studied 22 young adults with complete brachial plexus palsy who had surgical repair an average of 5 months after trauma. Sural nerve grafts connected the C5 root to the anterior division and the C6 root to the posterior division of the upper trunk. When the C6 root was not available, the posterior division of the upper trunk was repaired by means of a nerve transfer. In all cases except one, the suprascapular nerve was repaired via a nerve transfer. Outcomes were assessed an average of 35 months after surgery, focusing on recovery of muscle strength, categorized using the Medical Research Council scale. We compared the results obtained after a single root graft, either C5 (n = 11) or C6 (n = 1), with those observed after double root grafting (i.e., C5 + C6; n = 9). The single case of 3 roots available for grafting was excluded for this comparative study.

RESULTS

With grafting of the anterior division of the upper trunk, 17 of the 22 patients (n = 15) regained useful pectoralis major and biceps function of at least M3. Grafting the anterior and the posterior divisions of the upper trunk resulted in 18 of the 22 patients (n = 18) recovering shoulder abduction-adduction and either elbow flexion or extension. In only 5 cases (5 of 22 patients), however, was shoulder abduction-adduction achieved with concomitant recovery of both elbow flexion and extension. Grafting the posterior division of the upper trunk did not enhance the recovery of shoulder abduction, but it did restore elbow extension in approximately 6 of the 9 patients. In terms of muscle strength, an average of 2.3 muscles scored M3 or M4 in the single-root group, compared with 3.1 in the C5/C6 group (p < .05). The relative probability of recovering elbow flexion and shoulder adduction did not differ between patients with 1 versus 2 root grafts. The results of nerve transfers to the posterior division and of forearm muscle reinnervation were poor.

CONCLUSIONS

Grafting the divisions of the brachial plexus ensured multiple function reconstruction in 18 of the 22 patients (n = 18). However, only 5 of 22 patients (n = 4) experienced restoration of elbow flexion and extension.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Pain after avulsion injuries and complete palsy of the brachial plexus: the possible role of nonavulsed roots in pain generation

OBJECTIVE

Pain after complete brachial palsy has been attributed to the deafferentation of the spinal cord subjected to root avulsion. However, the large majority of patients have at least one nonavulsed root. We postulated that pain, be it subacute or chronic, originates in the stump of the nonavulsed roots.

METHODS

Thirty-six patients underwent brachial plexus grafting within 8 months of their initial injury. Ten other patients with palsy that had lasted for more than 2 years underwent selective, computed tomography-guided anesthetic blocks of the nonavulsed root. Pain was evaluated at different intervals, using a numerical scale ranging from 0 (no pain) to 10 (severe pain).

RESULTS

In all groups, pain decreased substantially or disappeared after a local anesthetic block or grafting. In the patients who underwent grafting, pain reduction was noted the first day after surgery in 56% of the 36 patients. Three weeks after surgery, pain decreased dramatically, by 80% (P < 0.001). By 12 months after surgery, pain had decreased by 90%, and within 24 months, by 95%. Only the difference between 3 weeks and 24 months after surgery was significant (P < 0.001). At final evaluation, 80% of the patients receiving grafts reported either no or minimal pain.

CONCLUSION

Our data suggest that nonavulsed roots mediate pain in subacute and chronic complete brachial plexus palsy.

Evaluation and management of peripheral nerve injury

Common etiologies of acute traumatic peripheral nerve injury (TPNI) include penetrating injury, crush, stretch, and ischemia. Management of TPNI requires familiarity with the relevant anatomy, pathology, pathophysiology, and the surgical principles, approaches and concerns. Surgical repair of TPNI is done at varying time intervals after the injury, and there are a number of considerations in deciding whether and when to operate. In neurapraxia, the compound muscle and nerve action potentials on stimulating distal to the lesion are maintained indefinitely; stimulation above the lesion reveals partial or complete conduction block. The picture in axonotmesis and neurotmesis depends on the time since injury. The optimal timing for an electrodiagnostic study depends upon the clinical question being asked. Although conventional teaching usually holds that an electrodiagnostic study should not be done until about 3 weeks after the injury, in fact a great deal of important information can be obtained by studies done in the first week. Proximal nerve injuries are problematic because the long distance makes it difficult to reinnervate distal muscles before irreversible changes occur. Decision making regarding exploration must occur more quickly, and exploration using intraoperative nerve action potential recording to guide the choice of surgical procedure is often useful.

Functional assessment of C-5 ventral rootlets by intraoperative electrical stimulation of the supraclavicular segment of the long thoracic nerve during brachial plexus surgery

Object

Anatomical and functional assessment of the intradural segment of the spinal nerves is imperative in brachial plexus surgery, as the repair of postganglionic elements in the setting of a confirmed nerve root avulsion is of no benefit. None of the current techniques to detect these avulsions can provide full information that ensures the functional status of the preganglionic segment of the roots. The objective of this study was to evaluate intraoperative electrical stimulation of the supraclavicular segment of the long thoracic nerve (LTN) as a method to differentiate C-5 nerve root extraforaminal rupture from its intradural avulsion.

Methods

The author performed a prospective analysis of data obtained in 14 patients presenting with the loss of C-5 nerve root function secondary to traumatic brachial plexus injury. The patients were divided into 2 groups: 8 patients in whom the intradural segment of C-5 nerve root was preserved (5 cases of closed traction injuries in whom the computed tomography [CT] myelograms confirmed the integrity of C-5 root and 3 cases of open sharp injuries) and a control group of 6 patients in whom CT myelography demonstrated avulsion of the root.

Results

The results of the intraoperative electrical stimulation of the LTN and the surgical outcome of each patient were recorded. The LTN electrical stimulation elicited serratus anterior muscle contraction in cases in which C-5 root was not avulsed, and there were no responses in patients whose radiological evaluation had demonstrated nerve root avulsion. In those patients in whom LTN stimulation proved to be positive, the C-5 root was used as a graftable stump to the suprascapular nerve and/or to the posterior division of the superior trunk. In these cases, favorable results were observed regarding arm abduction in all cases—Medical Research Council Grades M3 (37%) and M4 (62%). In the control group, the C-5 root was not used as a donor stump and a multiple nerve transfer technique was adopted as the preferred surgical option.

Conclusions

Intraoperative electrical stimulation of the supraclavicular segment of the LTN is a useful complementary method to test the functional status of the C-5 ventral rootlets. If the test is positive (that is, a response is present) it is indicative of extraforaminal rupture of the root, and if negative, it is suggestive of its avulsion.