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Neurosurgery does not claim to have improved surgery of the brachial plexus. But achievements in microsurgery have advanced surgical possibilities in several faculties. Neurosurgery for example has introduced considerable improvements concerning the assessment of intraforaminal or intraspinal root injuries. Intraoperative inspections of roots via hemi-laminectomy allowed to determine specificity and sensitivity of modern radiological imaging by correlating intraoperative findings with the results of the radiological imaging. Using determined axial MRI with thin sections, we showed root avulsion in a very high quantity. These findings led us to modify our surgical concept. Operations with long exploration were reduced and preoperative planning of neurotisation was improved due to the preoperative diagnostics.

Introduction: Neuropathic pains often cause social disintegration of the patients, encouraging us to apply microsurgical techniques to peripheral nerve lesions, but there are limitations and risks to take into account when handling scarred nerve tissue., Facts and Theoretical Considerations: The historical development of our microanatomical knowledge of grading of nerve lesions as well as facts on different fibrotic intraneural reactions are pointed out and additionally compared to today's theories of the origin of neuropathic pains., Methods: The microsurgical methods applied to entrapment syndromes, pseudoneuroma and neuroma formations consist of either external and interfascicular neurolysis or nerve grafting depending on the estimated grade of nerve lesion. If we primarily don't try to restore motor function after a nerve lesion but intend to achieve reduction of neuropathic pain due to a scarred nerve, the well-known methods of neuromodulation or thermic/cryoneurotomy increasingly become the treatment of choice., Conclusions: There is no real mental connection existing between our successful microsurgical methods on restoration of nerve function and the theories of the origin of neuropathic pains. We do treat pain of nociceptive origin by means of neurolysis but have abandoned these methods more and more in the case of chronic neuropathic pain. But on the other hand, the neuromodulation and neurotomy methods preferred in these cases still have limitations in compatibility and success rates. In a few cases we even risk inducing or worsening chronic neuropathic pains by means of microsurgery and/or neurotomy of a lesioned nerve.

In vivo visualization of the neuromuscular junction with epifluorescence imaging techniques has become a successful method of observing the ongoing process of re-occupation by regenerating motor axons of former post-synaptic sites after nerve injury. By using a light-integrating video camera for digital documentation, all parts of the neuromuscular junction can be visualized, as detailed as when documented with high-speed film, but with a minimum light intensity to prevent damage of neural or muscular structures. Results from comparisons of pre- and post-synaptic staining indicate a non-reoccupation rate up to 37 percent at a 55-day interval after nerve transfer, and up to 34 percent at a 66-day postoperative interval. Morphologic findings suggest that these high non-reoccupation rates are caused jointly by intramuscular missprouting, an insufficient intramuscular guidance apparatus, and intramuscular microneuroma formation at the insufficient neuromuscular junction.

The surgical outcome of traumatic injuries of the brachial plexus (BP) depends on the following parameters: 1) accurate preoperative diagnosis of cervical root avulsion; 2) time interval between injury and surgery; 3) delicate handling of the nerve tissue; and 4) postoperative physiologic training. This report is based on a 15-year experience in brachial plexus surgery and is supported on the grounds of two major studies. In a prospective study, the authors controlled for the reliability of preoperative radiologic diagnosis by myelo-CT and MRI scans for 40 patients, to evaluate the integrity of the intraspinal cervical roots after brachial plexus injury. Surgical inspection via a cervical hemilaminectomy proved the accuracy of 85 percent and 52 percent of CT myelography and MRI, respectively. Retrospective statistical analyses were carried out of the long-term surgical results of 54 patients with traumatic injuries of the BP who received a grafting procedure between cervical roots C5 or C6 and the musculocutaneous nerve. Patients operated on up to 6 months after trauma showed a better result than patients operated on later than 12 months after trauma (p<0.05). In contrast, grafting between cervical root C5 or C6 and the use of different sural-graft sizes to reconstruct the musculocutaneous nerve demonstrated no statistically significant difference in the final outcome.

Over the last 16 years, 345 surgical reconstructions of the brachial plexus were performed using nerve grafting or neurotization techniques in the Neurosurgical Department at the Nordstadt Hospital, Hannover, Germany. Sixty-five patients underwent graft placement between the C-5 and C-6 root and the musculocutaneous nerve to restore the flexion of the arm. A retrospective study was conducted, including statistical evaluation of the following pre- and intraoperative parameters in 54 patients: 1) time interval between injury and surgery; 2) choice of the donor nerve (C-5 or C-6 root); and 3) length of the grafts used for repairs between the C-5 or C-6 root and the musculocutaneous nerve. The postoperative follow-up interval ranged from 9 months to 14.6 years, with a mean +/- standard deviation of 4.4 +/- 3 years. Reinnervation of the biceps muscle was found in 61% of the patients. Comparison of the different preoperative time intervals (1-6 months, 7-12 months, and > 12 months) showed a significantly better outcome in those patients with a preoperative delay of less than 7 months (p < 0.05). Reinnervation of the musculocutaneous nerve was demonstrated in 76% of the patients who underwent surgery within the first 6 months postinjury, in 60% of the patients with a delay of between 6 and 12 months, and in only 25% of the patients who underwent surgery after 12 months. Comparison of the final outcome according to the root (C-5 or C-6) that was used for grafting the musculocutaneous nerve showed no statistical difference. Furthermore, statistical analysis (regression test) of the length of the grafts between the donor (C-5 or C-6 root) nerve and the musculocutaneous nerve displayed an inverse relationship between the graft length and the postoperative outcome. Together, these results provide additional information to enhance the functional outcome of brachial plexus surgery.

Surgical management and prognosis of traction injuries of the brachial plexus depend on the accurate diagnosis of root avulsion from the spinal cord. Myelography, computerized tomography (CT) myelography, and recently magnetic resonance (MR) imaging have become the main radiological methods for preoperative diagnosis of cervical root avulsions. Most of the previous studies on the accuracy of CT myelography and MR imaging studies have correlated the radiological findings with the extraspinal surgical findings at brachial plexus surgery. Surgical experience shows that in many cases extraspinal findings diverge from intradural determinations. Consequently, only correlation with the intradural surgical findings will allow assessment of the factual accuracy of CT myelography and MR imaging studies. In a prospective study, 135 cervical roots (C5-8) were evaluated by CT myelography and/or MR imaging and further explored intradurally via a hemilaminectomy. The accuracy of the preoperative CT myelography-based diagnosis in relation to the intraoperative findings was 85%. On the other hand, MR imaging demonstrated an accuracy of only 52%. The most common reasons for false-positive or false-negative findings were: 1) partial rootlet avulsion; 2) intradural fibrosis; and 3) dural cystic lesions. Computerized tomography myelography scans using 1- to 3-mm axial slices prove to be the most reliable method to evaluate preoperatively the presence of complete or partial root avulsion in traumatic brachial plexus injuries. Because extradural judgment of cervical root avulsion can be unreliable, accurate assessment of intraspinal root avulsion enormously simplifies the decision concerning the choice of donor nerves for transplantation and/or neurotization during brachial plexus surgery.

A review of our century's efforts to overcome nerve defects reveals the conclusion that today microsurgical techniques and interfascicular nerve grafting offer the best chances to get success in peripheral nerve repair. There exists a theoretical grading system of Sunderland, which enables us to understand the very different factors which might influence the sprouting of nerve fibers within the damaged or repaired nerve segments. But in practice, the indication to operate always depends on our own decision. The neurological status and electrophysiological tests can only sometimes facilitate our treatment and judgement on peripheral nerve lesions. The basic principles of microsurgical nerve repair are still valid. Modern techniques have resulted in better prognosis. Vast mobilization to achieve neurorrhaphy by force is obsolete today. Epineural trunk-to-trunk-suture is only allowed after clean cut-injuries. In all other cases we have to prefer a repair by autologous grafting. But some factors still remain which limits our efforts, such as muscle degeneration depending on time interval or ischemic fibrosis after the lesion, direct trauma to the muscle substance or a lesion in the region of nerve ramifications.