Clinical review of radial nerve injury

Biomechanical testing of osteosynthetic locking plates for proximal humeral shaft fractures - a systematic literature review

Proximal humeral shaft fractures can be treated with helically deformed bone plates to reduce the risk of iatrogenic nerve lesion. Controversially to this common surgical technique that was first established in 1999, no biomechanical investigation on humeral helical plating is recorded by other reviews, which focus on proximal fractures exclusively. Does an additional scope for shaft fractures reveal findings of helical testing? The present systematic literature review was performed based on guidelines by Kitchenham et al. to systematically search and synthesize literature regarding biomechanical testing of osteosynthetic systems for proximal humeral shaft fractures. Therefore, a systematic approach to search and screen literature was defined beforehand and applied on the findings of the database PubMed®. Synthesized information of the included literature was categorized, summarized and analyzed via descriptive statistics. Out of 192 findings, 22 publications were included for qualitative synthesis. A wide range of different test methods was identified, leading to a suboptimal comparability of specific results between studies. Overall, 54 biomechanical test scenarios were identified and compared. Physiological based boundary conditions (PB-BC) were referenced in 7 publications only. One study of testing straight and helical dynamic compression plates without PB-BCs was identified, showing significant differences under compressional loading. The absence of test standards of specific fields like humeral fractures lead to a high variance in biomechanical testing of osteosynthetic locking plates for proximal humeral shaft fractures. Physiological approaches offer realistic test scenarios but need to be uniformed for enhanced comparability between studies. The impact of helically deformed locking plates under PB-BC was not identified in literature.

Humeral Shaft Fractures: A Literature Review on Current Treatment Methods

In this review, we aim to provide a concise yet comprehensive summation of the assessment and management of humeral shaft fractures. These are uncommon but prevalent enough that they are part of any trauma surgeon's scope of practice. They have historically been treated using non-operative methods, including braces and casts, supported by published excellent results in the rate of the bone union. However, recently published studies challenge these results and suggest the outcomes might be better with surgery, but the complications of an operation such as infection and nerve injury can not be overlooked. In summary, non-surgical treatment is still the gold standard in the treatment of these fractures, but the indications for surgical management are now clearer and include early signs of delayed union and patients who are unable to have a brace fitted or are uncompliant. It is likely that these new developments will start to change practice, and therefore the treatment of humeral shaft fractures should be a topic of interest of any clinician who deals with them.

Comparing iatrogenic radial nerve lesions in humeral shaft fractures treated with helical or straight PHILOS plates: a 10-year retrospective cohort study of 62 cases

BACKGROUND

Humerus shaft fractures are common and often treated surgically with a proximal humerus internal locking system like the long PHILOS^® plate. Due to its close anatomical proximity to the humerus, the radial nerve is particularly susceptible to traumatic and iatrogenic damage. The iatrogenic radial nerve damage associated with internal locking systems is described in about 7% of the cases. In order to avoid this lesion, helical plates have been suggested since 1999. This technique continues to not being used as standard as there is still a clear lack of evidence. This study aimed to understand if twisting a long PHILOS plate can reduce the rate of iatrogenic radial nerve damage in humerus shaft fractures.

METHODS

In this 10-year retrospective comparative study, patients with primary traumatic proximal humerus shaft fracture treated with a straight or twisted helical PHILOS^® plate were analyzed and compared. Among the 62 patients meeting the inclusion criteria between 2008 and 2018, 33 received a conventional straight plate, while 29 were treated with a helical plate. The primary endpoint was iatrogenic radial nerve damage immediately after surgery with a follow-up of at least 3 months.

RESULTS

No case of radial nerve damage was reported in the helical group. In the control group, iatrogenic radial nerve damage occurred in two cases (6%), which was not statistically significant when comparing both groups (p = 0.18).

CONCLUSION

Manually twisting long PHILOS^® plates is a safe procedure to avoid radial nerve lesion in humerus shaft fractures. Even though the group size did not allow a statistically relevant difference, we underline that only the helical group showed no iatrogenic radial lesion. This technique deserves further attention.

LEVEL OF EVIDENCE

Level 3, retrospective cohort study.

The treatment of distal third humeral diaphyseal fractures: Is there still a place for the external fixation?

INTRODUCTION

The treatment for humeral diaphyseal fractures is still controversial. The purpose of this study was to evaluate the clinical and radiographic outcomes of treating humeral distal third diaphyseal fractures by using external fixation technique.

MATERIALS AND METHODS

We retrospectively review 65 cases of diaphyseal humeral fractures (31 type A, 23 type B and 11 type C of the AO/OTA classification) treated with external fixation (Orthofix FAD small) between 2008 and 2013. The mean follow-up was 48 months (24-72 months). There were 12 open fractures; however, no cases of concomitant vascular injury were described. The transolecranic traction was always applied to promote partial reduction through ligamentotaxis. In case of interposition of soft tissues impeding reduction, a small incision was performed allowing mobilization of bone ends.

RESULTS

All fractures resulted healed at a mean of 11 weeks (range 9-13 weeks); the average time of removal of the external fixator was 88 days (range 65-95 days). At the last follow-up, the mean elbow flexion was 132.6° (Min 126°-Max 137°) and the mean elbow extension was 6.4° (Max 0°-Min 13°). The Cassebaum's index rated as excellent in 47.8 % (31 patients), good in 37 % (24 patients), fair in 9.2 % (6 patients) and poor in 6 % (4 patients). The mean DASH score at the final follow-up was 14.7 (range 0-33); 15 patients had a range score between 10 and 20, 43 had less than 10, and seven had more than 20. We observed three cases of superficial infections and two cases of acute radial nerve palsy recovered within 3 months.

CONCLUSION

According to the excellent clinical results and full rate of consolidation, we state external fixation as a valid option in the treatment of distal third humeral diaphyseal fractures.

When is the best time to fix fractures?

The best time to operate on a fracture is governed in part by the nature of the fracture itself. It is also influenced by the premorbid condition of the patient and by the degree that associated injuries have disrupted normal processes. It is likely that some patients have a period of increased physiological risk for intervention, during which a second insult will result in further harm. The picture is not yet fully clear but relates to variations in the inflammatory response to trauma. One consistent lesson appears to resonate throughout the published literature. The most predictable risk factor for iatrogenic physiological disturbance is transfer to the operating theatre before adequate resuscitation of the patient has taken place.

Motor Nerve Transfers

Brachial plexus and peripheral nerve injuries are exceedingly common. Traditional nerve grafting reconstruction strategies and techniques have not changed significantly over the last 3 decades. Increased experience and wider adoption of nerve transfers as part of the reconstructive strategy have resulted in a marked improvement in clinical outcomes. We review the options, outcomes, and indications for nerve transfers to treat brachial plexus and upper- and lower-extremity peripheral nerve injuries, and we explore the increasing use of nerve transfers for facial nerve and spinal cord injuries. Each section provides an overview of donor and recipient options for nerve transfer and of the relevant anatomy specific to the desired function.

Management of Humeral Shaft Fractures With Intramedullary Interlocking Nail Versus Locking Compression Plate

Surgical fixation of humeral shaft fractures generally involves plating or nailing. It is unclear whether one method is more effective than the other. The aim of this study was to compare the results of the intramedullary nail and locking compression plate for the treatment of humeral shaft fractures. A total of 60 patients with humeral shaft fractures were randomized to undergo surgery with an intramedullary interlocking nail (n=30) or locking compression plate (n=30). The outcome was assessed in terms of intraoperative blood loss, operative time, hospital stay, union time, union rate, functional outcome, and incidence of complications. Functional outcome was assessed using the Constant score and the American Shoulder and Elbow Surgeons (ASES) score. Intraoperative blood loss, operative time, and hospital stay in group A (intramedullary interlocking nail) were significantly lower than those in group B (locking compression plate). No statistically significant difference was found regarding the union rate, mean Constant score, and mean ASES score between the groups. The average union time was found to be significantly lower for the intramedullary interlocking nail compared with the locking compression plate. The incidence of complications such as radial nerve palsy was found to be higher with the locking compression plate compared with the intramedullary interlocking nail. The intramedullary interlocking nail can be considered a better surgical option for the management of humeral shaft fractures because it offers decreased intraoperative blood loss; shorter operative times, hospital stays, and union times; and a lower incidence of serious complications such as radial nerve palsy.

Review of literature of radial nerve injuries associated with humeral fractures-an integrated management strategy

Background

Radial nerve palsy associated with fractures of the shaft of the humerus is the most common nerve lesion complicating fractures of long bones. However, the management of radial nerve injuries associated with humeral fractures is debatable. There was no consensus between observation and early exploration.

Methods and Findings

The PubMed, Embase, Cochrane Central Register of Controlled Trials, Google Scholar, CINAHL, International Bibliography of the Social Sciences, and Social Sciences Citation Index were searched. Two authors independently searched for relevant studies in any language from 1966 to Jan 2013. Thirty studies with 2952 humeral fractures participants were identified. Thirteen studies favored conservative strategy. No significant difference between early exploration and no exploration groups (OR, 1.03, 95% CI 0.61, 1.72; I² = 0.0%, p = 0.918 n.s.). Three studies recommend early radial nerve exploration in patients with open fractures of humerus with radial nerve injury. Five studies proposed early exploration was performed in high-energy humeral shaft fractures with radial nerve injury.

Conclusions

The conservative strategy was a good choice for patients with low-energy closed fractures of humerus with radial nerve injury. We recommend early radial nerve exploration (within the first 2 weeks) in patients with open fractures or high-energy closed fractures of humerus with radial nerve injury.

Management of radial nerve palsy following fractures of the humerus

Radial nerve palsy is the most common peripheral nerve injury following a humerus fracture, occurring in 2% to 17% of cases. Radial nerve palsies associated with closed humerus fractures have traditionally been treated with observation, with late exploration restricted to cases without spontaneous nerve recovery at 3 to 6 months. Advocates for early exploration believe that late exploration can result in increased muscular atrophy, motor endplate loss, compromised nerve recovery upon delayed repair, and significant interval loss of patient function and livelihood. In contrast, early exploration can hasten nerve injury characterization and repair, and facilitate early fracture stabilization and rehabilitation.

Biomechanical contributions of posterior deltoid and teres minor in the context of axillary nerve injury: a computational study

PURPOSE

To determine whether transfer to only the anterior branch of the axillary nerve will restore useful function after axillary nerve injury with persistent posterior deltoid and teres minor paralysis.

METHODS

We used a computational musculoskeletal model of the upper limb to determine the relative contributions of posterior deltoid and teres minor to maximum joint moment generated during a simulated static strength assessment and to joint moments during 3 submaximal shoulder movements. Movement simulations were performed with and without simulated posterior deltoid and teres minor paralysis to identify muscles that may compensate for their paralysis.

RESULTS

In the unimpaired limb model, teres minor and posterior deltoid accounted for 16% and 14% of the total isometric shoulder extension and external rotation joint moments, respectively. During the 3 movement simulations, posterior deltoid produced as much as 20% of the mean shoulder extension moment, whereas teres minor accounted for less than 5% of the mean joint moment in all directions of movement. When we paralyzed posterior deltoid and teres minor, the mean extension moments generated by the supraspinatus, long head of triceps, latissimus dorsi, and middle deltoid increased to compensate. Compensatory muscles were not fully activated during movement simulations when posterior deltoid and teres minor were paralyzed.

CONCLUSIONS

Reconstruction of the anterior branch of the axillary nerve only is an appropriate technique for restoring shoulder abduction strength after isolated axillary nerve injury. When shoulder extension strength is compromised by extensive neuromuscular shoulder injury, reconstruction of both the anterior and posterior branches of the axillary nerve should be considered.

CLINICAL RELEVANCE

By quantifying the biomechanical role of muscles during submaximal movement, in addition to quantifying muscle contributions to maximal shoulder strength, we can inform preoperative planning and permit more accurate predictions of functional outcomes.

Radial nerve palsy associated with humeral shaft fracture. Is the energy of trauma a prognostic factor?

BACKGROUND

Radial nerve palsy associated with humeral shaft fractures is the most common nerve lesion complicating fractures of long bones. The purpose of the study was to review the outcome of surgical management in patients with low energy and high energy radial nerve palsy after humeral shaft fractures.

METHODS

Eighteen patients were treated operatively for a humeral shaft fracture with radial nerve palsy. The mean age was 32.2 years and the mean follow up time was 66.1 months (range: 30-104). The surgical management included fracture fixation with early nerve exploration and repair if needed. The patients were divided in two groups based on the energy of trauma (low vs. high trauma energy). The prevalence of injured and unrecovered nerves and time to nerve recovery were analysed.

RESULTS

Five patients sustained low and 13 high energy trauma. All patients with low energy trauma had an intact (4) or entrapped (1) radial nerve and recovered completely. Full nerve recovery was also achieved in five of 13 patients with high energy trauma where the nerve was found intact or entrapped. Signs of initial recovery were present in a mean of 3.2 weeks (range: 1-8) for the low energy group and 12 weeks (range: 3-23) for the high energy group (p=0.036). In these patients, the average time to full recovery was 14 and 26 weeks for the low and high energy trauma group respectively. Eight patients with high energy trauma had severely damaged nerves and failed to recover, although microsurgical nerve reconstruction was performed in 4 cases. Patients with high energy trauma had a prolonged fracture healing time (18.7 weeks on average) compared to those with low energy fractures (10.4 weeks), (p=0.003).

CONCLUSIONS

The outcome of the radial nerve palsy following humeral fractures is associated to the initial trauma. Palsies that are part of a low energy fracture uniformly recover and therefore primary surgical exploration seems unnecessary. In high energy fractures, neurotmesis or severe contusion must be expected. In this case nerve recovery is unfavourable and the patients should be informed of the poor prognosis and the need of tendon transfers.

Median to radial nerve transfer to restore wrist and finger extension: technical nuances

BACKGROUND

Traditional methods for restoring finger and wrist extension following radial nerve palsy include interposition nerve grafting or tendon transfers. We have described the utilization of distal nerve transfers for the restoration of radial nerve function in the forearm.

OBJECTIVE

We review the neuroanatomy of the forearm and outline the steps required for the implementation of this transfer.

METHODS AND RESULTS

We use a step-by-step procedural outline and detailed photographs, line drawings, and video to describe the procedure.

CONCLUSION

This approach is technically feasible and is a reconstructive option for patients with this nerve deficit.

Late-onset radial nerve palsy associated with conservatively managed humeral fracture. A case report and suggested classification system

Radial nerve palsy can occur with humerus fracture, either at the time of injury (primary) or during reduction (secondary). Late-onset radial nerve palsy (not immediately related to injury or reduction) has been very seldom reported in the English literature. We describe a case of late-onset radial nerve palsy, which developed 9 weeks after an attempted closed management of a midshaft humerus fracture. Exploration of the nerve was performed. The radial nerve was found to be stretched over the ends of the fracture. Open reduction and external fixation of the fracture with mobilization of the nerve from the fracture site lead to complete return of radial nerve function occurring by 3 months. We recommend exploration of cases of late-onset radial nerve palsy in contrast to primary or secondary radial nerve palsy, which can be treated conservatively. Our experience suggests that the cause of the palsy is a continuous ongoing pathology and not a single time event as in primary or secondary cases. Radial nerve palsies associated with humeral fracture should be classified as either primary (at the time of injury), secondary (at the time of reduction), or late onset (not related to either injury or reduction).

Management of radial nerve palsy associated with humeral shaft fracture: a decision analysis model

PURPOSE

When managing radial nerve palsy associated with a humerus fracture, both surgeon and patient must balance the risks and benefits of performing an invasive surgical procedure to address a functional deficit that is likely, but not certain, to recover with nonsurgical management. The purpose of this study was to better understand the determinants of optimal management strategy using expected-value decision analysis.

METHODS

Probabilities for the occurrences of the potential outcomes after initial observation or early surgery were determined from a systematic review of the literature. Scores for these outcomes were obtained from a questionnaire on patient preferences completed by 82 subjects without a history of humerus fracture and radial nerve palsy and used in the model as a measure of utility. A decision tree was constructed, fold-back analysis was performed to determine optimal treatment, and sensitivity analyses were used to determine the effect on decision making of varying outcome probabilities and utilities.

RESULTS

Observation was associated with a value of 8.4 and early surgery a value of 6.7 given the outcome probabilities and utilities studied in this model, making observation the optimal management strategy. When parameters were varied in sensitivity analysis, it was noted that when the rate of recovery after initial observation falls below 40% or when the utility value for successful early surgery rises above 9.4, early surgery is the preferred management strategy.

CONCLUSIONS

Initial observation was the preferred strategy. In clinical settings in which the likelihood of spontaneous recovery of nerve function is low or when an informed patient has a strong preference for surgery, early surgery may optimize outcome.

TYPE OF STUDY/LEVEL OF EVIDENCE

Economic and Decision Analysis II.

Early surgical exploration of radial nerve injury associated with fracture shaft humerus

The series included 36 patients, predominantly male, mean age 30.3 years. The most common cause of injury was motor car accident in 20 patients. Postreduction radial nerve injury occurred in nine cases. Open fracture humerus with radial nerve injury in seven cases. The fractures were situated in the middle or distal third of the humeral shaft. Most were transverse fractures. Twelve patients had surgery on the day of injury and the other 24 at a mean of 8 days later (3-14). Narrow dynamic compression plate was generally used for fixation. Exploration of the radial nerve demonstrated compression at the lateral intermuscular septum in 19 cases, entrapment in the fracture site in nine cases, and loss of its continuity in eight cases. Neurolysis was required in 20 cases, epineurorrhaphy in nine cases, interfascicular nerve grafts in five, and first-intention tendon transfer in two. Results of nerve surgery were assessed with the MRC (Medical Research Council) at a mean follow-up of 8.2 years. Outcome was rated good to excellent in 28 patients, fair in 1, and poor (failure) in 3. First-intention tendon transfers were performed in 2 patients and 2 patients were lost to follow-up. Mean delay to recovery was 7 months after neurolysis and nerve repair and 15 months after nerve grafts. The fracture was united in all cases. The mean time of union was 5 months.

Primary radial nerve palsy in patients with acute humeral shaft fractures

OBJECTIVE

The primary aim was to report on the recovery of radial nerve function in patients with acute closed humeral shaft fractures and associated primary radial nerve palsy. The secondary aim was to report on the long-term functional outcome and health-related quality of life (HRQoL) in patients with this specific injury.

SETTING

Six major hospitals in Stockholm County.

DESIGN

Descriptive study. Retrospective assessment of radial nerve recovery and fracture healing. Prospective assessment of functional outcome and HRQoL.

PATIENTS

Thirty-three patients with acute radial nerve palsy and a closed humeral shaft fracture in a population of 358 patients with 361 humeral shaft fractures.

INTERVENTION

Nonoperative or operative treatment as per decision of the attending orthopedic surgeon.

MAIN OUTCOME MEASUREMENTS

Recovery of the radial nerve, fracture healing, functional outcome according to the Short Musculoskeletal Function Assessment (SMFA) and the Disabilities of the Arm, Shoulder and Hand (DASH). HRQoL according to Short Form 36 (SF-36).

RESULTS

Among the 18 patients treated nonoperatively, 16 (89%) displayed a complete recovery from their radial nerve palsy while 2 (11%) presented minor sequelae. In 11 (73%) of the 15 patients treated primarily operatively, the nerve function recovered completely while 2 patients (13%) had minor sequelae and 2 (13%) had major sequelae, i.e. 1 partial nerve palsy and 1 total radial nerve palsy. Sixteen patients (48%) were available for assessment of the long-term functional outcome and HRQoL at a mean of 7 years (range, 6 to 8 years). The range of motion and the muscular strength of the injured arm, the functional outcome according to the SMFA, and HRQoL according to the SF-36 showed results comparable to those previously reported for patients with healed humeral shaft fractures without associated radial nerve palsy.

CONCLUSION

This study confirms the high spontaneous recovery rate of primary radial nerve palsies in patients with closed humeral shaft fractures. Primary radial nerve palsy should not be regarded as an isolated indication for primary surgical intervention.

Concomitant injuries to the ipsilateral shoulder in patients with a fracture of the diaphysis of the humerus

Antegrade intramedullary nailing of fractures of the shaft of the humerus is reported to cause impairment of the shoulder joint. We have reviewed 33 patients with such fractures to assess how many had injuries to the ipsilateral shoulder. All had an MR scan of the shoulder within 11 days of injury. The unaffected shoulder was also scanned as a control. There was evidence of abnormality in 21 of the shoulders (63.6%) on the injured side; ten had bursitis of the subacromial space, five evidence of a partial tear of the rotator cuff, one a complete rupture of the supraspinatus tendon, four inflammatory changes in the acromioclavicular joint and one a fracture of the coracoid process. These injuries may contribute to pain and dysfunction of the shoulder following treatment, and their presence indicates that antegrade nailing is only partly, if at all, responsible for these symptoms.

Courses of the radial nerve differ between chinese and Caucasians : clinical applications

We analyzed anatomic distribution of the radial nerve in the upper arms in Chinese-adult embalmed cadavers (120 nerves in 60 cadavers) and compared it with findings reported for Caucasian adults. The acromion, the medial epicondyle, and the lateral epicondyle were used as bony landmarks. We used previously described techniques to quantitatively describe the location of the radial nerve in relation to the surrounding skeleton. Courses of the radial nerve relative to the humeral shaft in Chinese subjects differed from those previously reported for Caucasian subjects. The parameters that differed from Caucasians were: the distances from the acromion to the upper margin (147 +/- 21 mm versus 124 +/- 12 mm), the acromion to the lower margin (195 +/- 36 mm versus 176 +/- 17 mm), and the medial epicondyle to the lower margin (111 +/- 21 mm versus 131 +/- 10 mm). Our study provides information to help identify the radial nerve during surgery and elucidates racial differences in the distribution of the radial nerve between Chinese and Caucasian populations.

Median to radial nerve transfer for treatment of radial nerve palsy. Case report

The purpose of this study is to report a surgical technique of nerve transfer to restore radial nerve function after a complete palsy due to a proximal injury to the radial nerve. The authors report the case of a patient who underwent direct nerve transfer of redundant or expendable motor branches of the median nerve in the proximal forearm to the extensor carpi radialis brevis and the posterior interosseous branches of the radial nerve. Assessment included degree of recovery of wrist and finger extension, and median nerve function including pinch and grip strength. Clinical evidence of reinnervation was noted at 6 months postoperatively. The follow-up period was 18 months. Recovery of finger and wrist extension was almost complete with Grade 4/5 strength. Pinch and grip strength were improved postoperatively. No motor or sensory deficits related to the median nerve were noted, and the patient is very satisfied with her degree of functional restoration. Transfer of redundant synergistic motor branches of the median nerve can successfully reinnervate the finger and wrist extensor muscles to restore radial nerve function. This median to radial nerve transfer offers an alternative to nerve repair, graft, or tendon transfer for the treatment of radial nerve palsy.

The radial nerve in the brachium: an anatomic study in human cadavers

PURPOSE

To explore the course of the radial nerve in the brachium and to identify practical anatomic landmarks that can be used to avoid iatrogenic injury during humerus fracture fixation.

METHODS

Data were collected from 27 adult cadaveric specimens, including 18 embalmed cadavers and 9 fresh-frozen limbs. Measurements were taken using osseous landmarks to define the relationship of the radial nerve and the posterior and lateral humerus. The extremities were studied further to determine the association of the radial nerve and anatomic landmarks on both longitudinal and cross-sectioned specimens.

RESULTS

A 6.3 cm +/- 1.7 segment of radial nerve was found to be in direct contact with the posterior humerus from 17.1 cm +/- 1.6 to 10.9 cm +/- 1.5 proximal to the central aspect of the lateral epicondyle, centered within 0.1 cm +/- 0.2 of the level of the most distal aspect of the deltoid tuberosity. The radial nerve lay in direct contact with the periosteum in all specimens, without evidence of a structural groove in the humerus in any specimen. On entering the anterior compartment, the radial nerve had very little mobility as it was interposed between the obliquely oriented lateral intermuscular septum and the lateral aspect of the humerus. As it extended distally, the nerve coursed anterior to the humerus and became protected by brachialis muscle at the level of the proximal aspect of the lateral metaphyseal flare.

CONCLUSIONS

The radial nerve is at risk of injury with fractures of the humerus and with subsequent operative fixation in 2 areas. The first is along the posterior midshaft region for a distance of 6.3 cm +/- 1.7 centered at the distal aspect of the deltoid tuberosity. The second is along the lateral aspect of the humerus in its distal third from 10.9 cm +/- 1.5 proximal to the lateral epicondyle to the level of the proximal aspect of the metaphyseal flare. The deltoid tuberosity is a consistent and practical anatomic landmark that can be used to determine the level of the radial nerve along the posterior aspect of the humerus during operative fixation from an anterior approach.

The role of microsurgery in nerve repair and nerve grafting

Advances in the field of microsurgery have improved the results after peripheral nerve surgery and have extended the types of nerve repair that can be accomplished. Innovative techniques using microsurgical dissection, such as nerve transfers and end-to-side repairs are direct consequences of these advances.

Radial nerve injuries associated with humeral fractures

A radial nerve injury associated with a humeral shaft fracture is an important injury pattern among trauma patients. It is the most common peripheral nerve injury associated with this fracture. Although treatment for this injury pattern is a controversial subject among upper-extremity surgeons, certain principles of management need to be applied in all cases. As our understanding of the pathoanatomy of the humerus and surrounding neurovascular structures has evolved, surgeons have adapted their strategies to improve outcome and avoid long-term morbidity. The principles of management and the clinical outcomes of various treatment strategies, defined in the literature, are reviewed in this article.

Radial nerve palsy associated with fractures of the shaft of the humerus

The management of radial nerve palsy associated with fractures of the shaft of the humerus has been disputed for several decades. This study has systematically reviewed the published evidence and developed an algorithm to guide management. We searched web-based databases for studies published in the past 40 years and identified further pages through manual searches of the bibliography in papers identified electronically. Of 391 papers identified initially, encompassing a total of 1045 patients with radial nerve palsy, 35 papers met all our criteria for eligibility. Meticulous extraction of the data was carried out according to a preset protocol.

The overall prevalence of radial nerve palsy after fracture of the shaft of the humerus in 21 papers was 11.8% (532 palsies in 4517 fractures). Fractures of the middle and middle-distal parts of the shaft had a significantly higher association with radial nerve palsy than those in other parts. Transverse and spiral fractures were more likely to be associated with radial nerve palsy than oblique and comminuted patterns of fracture (p < 0.001). The overall rate of recovery was 88.1% (921 of 1045), with spontaneous recovery reaching 70.7% (411 of 581) in patients treated conservatively. There was no significant difference in the final results when comparing groups which were initially managed expectantly with those explored early, suggesting that the initial expectant treatment did not affect the extent of nerve recovery adversely and would avoid many unnecessary operations. A treatment algorithm for the management of radial nerve palsy associated with fracture of the shaft of the humerus is recommended by the authors.

Fracture callus engulfing a peripheral nerve does not affect its function: an experimental study in rabbits

The fate of a peripheral nerve engulfed in fracture callus is not known. We investigated the impact of envelopment of the sciatic nerve by fracture callus using a New Zealand rabbit femoral fracture model. The sciatic nerve was mobilized and coiled around the ipsilateral femur, which was surgically fractured, shortened, and osteosynthesized. Bony union was achieved, and callus engulfed the sciatic nerve in all animals. Nerve function was evaluated clinically and by conduction studies preoperatively and postoperatively. Although the nerve function in terms of clinical evaluation, amplitude, motor latency, and spontaneous activity deteriorated immediately postoperatively, recovery was evident in the following weeks indicating that the detected nerve dysfunction was attributable to the surgical mobilization. In addition, histologic and quantitative histomorphometric analyses proved that in none of the animals did the callus compress the sciatic nerve whereas an impressive process of axonal regeneration took place despite callus maturation. Results of our study suggest that callus, engulfing a peripheral nerve, does not compress it and the nerve appears to be intact in an osseous canal. This results in preservation of the integrity and function of the nerve, which may have significant clinical applications.

Radial nerve palsy associated with high-energy humeral shaft fractures

PURPOSE

To determine whether the radial nerve should be explored when there is a complete sensory and motor deficit after a high-energy fracture of the humeral diaphysis.

METHODS

Twenty-four patients aged 16 years or older with a high-energy, diaphyseal fracture of the humerus and complete motor and sensory radial nerve palsy were reviewed retrospectively. Eleven fractures were open-6 of these were part of a very complex upper-extremity injury (multiple ipsilateral fractures in 3 patients and near amputation in 3). All 11 patients with open fractures and 3 of 13 patients with closed injuries had radial nerve exploration.

RESULTS

All 6 patients with a transected radial nerve had an open humerus fracture and were part of a complex upper-extremity injury. Five of 6 had primary repair of the radial nerve, and none recovered. All 8 intact explored nerves and 9 of 10 unexplored nerves recovered; the only nonrecovery occurred in a patient treated with closed intramedullary rod fixation who may have had iatrogenic nerve injury. The average time to initial signs of recovery was 7 weeks (range, 1-25 weeks). The average time to full recovery was 6 months (range, 1-21 months).

CONCLUSIONS

Transection of the radial nerve is usually associated with open fractures of the humerus that are part of a very complex upper-extremity injury. The results of primary nerve repair in this circumstance are poor, likely related to an extensive zone of injury and the need for nerve grafting. Intact nerves and nerve palsies that are part of a closed fracture nearly always recover, even after high-energy injuries. Because the first signs of nerve recovery and complete recovery of the nerve can be quite delayed, patience is merited before considering tendon transfers.

Radial nerve palsy after simple fracture of the humerus

Radial nerve palsy is a common complication of simple fracture of the humerus. The aim of this retrospective study was to assess the degree of spontaneous recovery and the need for exploration and repair of the nerve. The study included 26 patients with radial nerve palsy after simple fracture of the humerus. The male:female ratio was 3:1 and the median age was 21 years (range 9-79). Three patients had early exploration of the radial nerve in connection with osteosynthesis, and no appreciable damage to the nerve was found. Two other patients were explored later because they failed to recover. This exploration showed damage to the nerve which required further operation. Twenty-one patients were treated conservatively and all recovered well. None needed later operation. Because of the low incidence of nerve lesions we recommend an expectant policy initially.

The assessment and treatment of nerve dysfunction after trauma around the elbow

Nerve dysfunction after trauma around the elbow can lead to significant long-term pain and functional deficit. Fortunately, most of these injuries are neurapraxias that will recover spontaneously after conservative treatment. The necessity and time frame for surgical intervention for specific patterns of nerve dysfunction remains controversial. Often surgical exploration exacerbates rather than alleviates the presenting nerve problem. Distal humeral shaft fractures, elbow dislocations, Monteggia fracture-dislocations, supracondylar fractures in children, and proximal forearm trauma all have been associated with various types of nerve injuries with a variable degree of recovery. The early recognition of nerve dysfunction combined with appropriate treatment measures is the key to successful outcome.

Iatrogenic nerve injuries

Iatrogenic nerve injuries are an undesired byproduct of the practice of medicine and have been so since antiquity. The majority of such injuries occur perioperatively, and are, therefore, attributed to surgeons and anesthesiologists. Nonetheless, the members of almost every clinical specialty are at risk to some degree. Iatrogenic nerve injuries can affect almost any portion of the peripheral nervous system, and can result from many different causes. This article reviews many of the more common iatrogenic nerve lesions.

Alternative operative exposures of the posterior aspect of the humeral diaphysis with reference to the radial nerve

An anatomical study was performed to define the course of the radial nerve in the posterior aspect of the arm, with particular reference to its relationship to operative exposures of the posterior aspect of the humeral diaphysis. In ten cadaveric specimens, the radial nerve was found to cross the posterior aspect of the humerus from an average of 20.7 +/- 1.2 centimeters proximal to the medial epicondyle to 14.2 +/- 0.6 centimeters proximal to the lateral epicondyle. As it crossed the posterior aspect of the humerus in each specimen, the nerve had several branches to the lateral head of the triceps; however, no branches were found innervating the medial head of the triceps in the posterior aspect of any of the specimens. At the lateral aspect of the humerus, the nerve trifurcated into a branch to the medial head of the triceps, the lower lateral brachial cutaneous nerve, and the continuation of the radial nerve into the distal part of the upper arm and the forearm. Three operative approaches were performed in each specimen. The posterior triceps-splitting approach exposed an average of 15.4 +/- 0.8 centimeters of the humerus from the lateral epicondyle to the point at which the radial nerve crossed the posterior aspect of the humerus. For the second approach, the radial nerve was mobilized proximally to allow an additional six centimeters of the humeral diaphysis to be visualized. The third approach (the modified posterior approach) involved the identification of the radial nerve distally as it crossed the lateral aspect of the humerus, followed by reflection of both the lateral and the medial heads of the triceps medially. This exposure permitted visualization of 26.2 +/- 0.4 centimeters of the humeral diaphysis from the lateral epicondyle proximally. The results after use of the modified posterior approach in seven patients were also reviewed.

Radial nerve palsy caused by open humeral shaft fractures

Although radial nerve palsy associated with a closed humeral shaft fracture may be managed by observation, it is our experience that an open humeral shaft fracture with radial nerve palsy requires exploration of the nerve. In a series of 14 patients with radial nerve palsy caused by an open humeral shaft fracture, 9 (64%) of the 14 patients had a radial nerve that was either lacerated or interposed between the fracture fragments. There was an equal incidence of radial nerve lacerations or entrapments in types I, II, and III open humeral shaft fractures. Epineural radial nerve repair, done primarily or secondarily, provided a satisfactory return of radial nerve function. Rigid fixation of the associated fracture is the recommended treatment.

[Treatment procedure in humeral shaft fractures with primary or secondary radial nerve damage]

We give an account of 28 patients with fractured humerus diaphysis, suffering from primary and seven patients suffering from secondary lesion of the radialis nerve, all treated by operation. In each case the radialis nerve was exposed and the fracture was treated by fixation with compression plates. In case of primary lesions of the radialis nerve, we found intraoperative damages by traction (six times), contusions (seven times), intraneural hämatomas (six times) and for one time perforation of the nerve by bones. The rest of this group (eight times) did not show any pathological finding. Those patients with secondary lesion of the radialis nerve showed damages by traction (three times) and in two cases the nerve was walled up by callus or connective tissue. Two times we could not find any pathological alteration of the nerve. 23 (six) out of 28 (seven) patients with primary (secondary) lesion of the radialis nerve could be followed up. On this occasion we stated complete neurological restitution 20 times (four times) and incomplete restitution three times (two times). The great number of pathological findings, which necessitate operative treatment, the short duration of remission and the high rate of restitution confirm us to leave the way of conservative treatment in cases of primary or secondary lesion of the radialis nerve and the indication of acute operation is given.

Radial nerve lesions associated with fractures of the humeral shaft

Radial nerve palsy associated with a fracture of the shaft of the humerus is a relatively common injury. Out of 91 radial nerve injuries, operated upon in the Neurosurgical University Clinic in Belgrade from 1979 to 1988, 37 were associated with fractures of the humeral shaft or their surgical treatment. These fractures were previously treated in other medical units. In all cases a microsurgical reconstruction of the radial nerve was done: an interfascicular neurolysis in 24 cases and interfascicular grafting in 13 cases. A useful functional recovery was obtained in 91.9 per cent of the cases. Timing of nerve exploration and repair, as a main problem, is discussed.

Radial nerve laceration and retraction associated with a supracondylar fracture of the humerus

Supracondylar fracture of the humerus can be associated with varying degrees of radial nerve injury. Complete laceration of the nerve is rare. We report a case of radial nerve laceration after a supracondylar fracture in which the proximal segment of the nerve retracted into the axilla. Successful treatment resulted from long segmental sural nerve grafting.

Treatment of fractures of the shaft of the humerus accompanied by paralysis of the radial nerve

This paper reports the results of treatment of 17 patients with fractures of the shaft of the humerus accompanied by paralysis of the radial nerve in a series of 111 patients with fractures of the shaft of the humerus. In early operative explorations in 14 cases the radial nerve appeared undamaged in 13 cases. In cases where spontaneous recovery of the function of the radial nerve failed to occur, no evidence has been found that the delay in exploration influenced eventual motor recovery. The high incidence of undamaged nerves at exploration suggests that a conservative approach by collar and cuff or Sarmiento bracing is justified in such cases of fractures of the shaft of the humerus. Paralysis of the radial nerve associated with fractures of the shaft of the humerus is, in our opinion, not an indication for early operative treatment.

Radial palsy in shaft fracture of the humerus

Fifty-nine patients with immediate and 16 with secondary radial nerve palsy complicating a fracture of the shaft of the humerus were reviewed. According to the preferences of the surgeon in charge, the palsy was treated either with early exploration of the radial nerve and internal fixation of the fracture or with initial expectance. Of the latter, 12 were later explored. No useful recovery of motor function could be seen in 13/59 patients with immediate and in 2/16 patients with secondary palsy. In patients with immediate palsy treated by early exploration, there were 8/27 nonrecoveries. Among those treated with initial expectance, there were 5/32 nonrecoveries. For secondary palsy, these figures were 2/10 and 0/6, respectively. No support emerged for routine early exploration.

Immediate radial nerve palsy complicating fracture of the shaft of the humerus: when is early exploration justified?

A series of 59 patients with immediate complete radial nerve palsy complicating a fracture of the shaft of the humerus was analysed. In 27 patients the radial nerve was explored and the fracture was fixed within 3 weeks of the accident. In 12 other patients exploration was performed after an average of 17 weeks. The remaining 20 patients showed signs of spontaneous recovery within 4 months and were managed conservatively. The mean follow-up time was 3 years. At exploration, laceration, interposition between the fragments or entrapment of the radial nerve in callus was found significantly (P less than 0.01) more often with longitudinal fractures of the distal third (46 per cent) than with transverse fractures of the middle third, in which 85 per cent of the explored cases showed the nerve to be no more than slightly bruised. Useful recovery was seen in 46 patients (78 per cent of the whole series).

Radial nerve palsy associated with humeral fractures

Of 54 patients with radial nerve palsy complicating fractures of the humeral shaft, 93% improved after early surgical treatment whereas 82% improved with expectant treatment. Partial palsy of the radial nerve, whether immediate or delayed in onset, uniformly showed similar improvement with expectant treatment or with surgery. Of patients with delayed-onset radial palsy, 40% had a nerve lesion amenable to delayed surgery. All patients who did not recover radial nerve function had fractures involving the middle third of the humerus. The poorest prognosis for nerve recovery seemed to be in patients with comminuted, middle-third fractures who had radial nerve palsy of immediate onset-a situation indicating the severity of the injury.