Pain syndromes after missile-caused peripheral nerve lesions: part 2--treatment

Concepts of Pain Management Following Nerve Injuries: Multidisciplinary Approach

Purpose

A systematic review to identify treatment approaches for the management of pain following peripheral nerve injury.

Methods

A published literature search was performed for the concepts of peripheral nerve injury and pain management with related synonyms. The strategies were created using a combination of controlled vocabulary terms and keywords and were executed in Embase.com, Ovid-Medline All, and Scopus from database inception. Database searches were completed on August 22, 2023.

Results

The initial search resulted in a total of 1,793 citations. In total, 724 duplicates were removed, leaving 1,069 unique citations remaining for analysis. This review excluded all papers that were not specific to pain following peripheral nerve injury. Case and cohort studies (n < 5) were also excluded. Thirty-two articles on pain management strategies after peripheral nerve injury remained, with years of publication ranging from 1981 to 2023. An additional four articles were identified by manual search. Of the 36 articles reviewed, 15 articles reported on the approach to the treatment of pain after a peripheral nerve injury, and the other 22 articles consisted of cohort and case series studies.

Conclusions

There is a lack of literature describing efficacy of various treatment strategies for pain following peripheral nerve injuries. Few studies provide clear, stepwise clinical guidance for practicing physicians and other health care providers on the treatment of these complicated patients.

A Brief History of Peripheral Nerve Surgery in Serbia

Peripheral nerve surgery in Serbia has become the most fruitful subsection of national neurosurgery, with international recognition of Serbian surgeons and institutions. We chronicle landmark events in the history of the field in Serbia, highlighting the development of the field over time and outlining future prospects. This manuscript provides an example of the development of peripheral nerve surgery and associated training in a challenging social, political, and economic context and may guide the development of peripheral nerve surgery care and training in other settings.

Useful functional recovery and quality of life after surgical treatment of peroneal nerve injuries

Closed injuries to the peroneal nerve recover spontaneously in about a third of patients, but surgery may be needed in the remaining 2/3. The recovery after surgery is not always satisfactory and the patients may need an orthosis or a walking aid to cope with regular daily activities. This study aimed to evaluate the useful functional recovery and quality of life (QoL) in surgically treated patients with peroneal nerve (PN) injuries. The study involved 51 patients who have undergone surgical treatment due to PN injury in our department, within a 15-year period (2006-2020). Thirty patients (59%) were treated with neurolysis, 12 (23%) with nerve repair techniques, and 9 (18%) with tendon transfer (TT). Neurolysis is employed in the least extensive nerve injuries when nerve continuity is preserved and yields a motor recovery ratio of almost 80%. Nerve repairs were followed by 58.33% of patients achieving M3+ recovery, while 41.66% recovered to the useful functional state (M4 or M5) With the use of TTs, all patients recovered to the M3+, while 66.7% recovered to M4. All our results correspond to the results of previous studies. No statistically significant differences were found regarding the QoL of the groups. There is an apparent advantage of neurolysis, over nerve repair, over TT procedure, both in terms of useful functional recovery, and foot-drop-related QoL. However, when involving all aspects of QoL, these advantages diminish. The individual approach leads to optimal results in all groups of patients.

Resident peripheral nerve surgery competence: An assessment of procedural exposure, self-reported competence and technical ability

BACKGROUND

Identifying peripheral nerve surgery procedure (PNSP) competencies is crucial to ensure adequate resident training. We examine PNSP training at neurosurgical centers in the US and Canada to compare resident-reported competence, PNSP exposure, and resident technical abilities in performing 3 peripheral nerve coaptations (PNC).

METHODS

Resident-reported PNSP competence and PNSP exposure data were collected using questionnaires from neurosurgical residents at North American neurosurgical training centers. Exposure and self-reported competency were correlated with technical skills. Technical PNC variables collected included: time-to-completion, nerve-handling from video-analysis, independent and blinded visual-analog-scale (VAS) PNC quality grading by 3 judges, and training level.

RESULTS

A total of 40 neurosurgical residents participated in the study. Although self-reported competency scores correlated with procedural exposure (P < 0.01, rs = 0.88), a discrepancy was found between the degree of self-reported competency and amount of exposure. The discrepancy was greater in senior residents. A significant VAS difference was found between PNC types with the direct-suture and connector-assister groups scoring higher than connector-only (P = 0.02, P < 0.01, respectively). No difference was observed between training level and VAS grading, nor time-to completion (P = 0.33 and 0.25, respectively). No correlation was found between self-reported competency performing PNSPs and PNC VAS scores, nor nerve handling.

CONCLUSIONS

Despite more exposure and a higher self-reported PNSP competency in senior residents, no difference was seen between senior/junior residents in PNC quality. A discrepancy in PNSP exposure and self-reported competency exists. This information will provide guidance for the direction of resident PNS training.

Pain Relief after Surgical Decompression of the Distal Brachial Plexus

Background  Brachial plexopathy causes pain and loss of function in the affected extremity. Entrapment of the brachial plexus terminal branches within the surrounding connective tissue, or medial brachial fascial compartment, may manifest in debilitating symptoms. Open fasciotomy and external neurolysis of the neurovascular bundle in the medial brachial fascial compartment were performed as a surgical treatment for pain and functional decline in the upper extremity. The aim of this study was to evaluate pain outcomes after surgery in patients diagnosed with brachial plexopathy.

Methods  We identified 21 patients who met inclusion criteria. Documents dated between 2005 and 2019 were reviewed from electronic medical records. Chart review was conducted to collect data on visual analog scale (VAS) for pain, Semmes-Weinstein monofilament test (SWMT), and Medical Research Council (MRC) scale for muscle strength. Pre- and postoperative data was obtained. A paired sample t -test was used to determine statistical significance of pain outcomes.

Results  Pain severity in the affected arm was significantly reduced after surgery (pre: 6.4 ± 2.5; post: 2.0 ± 2.5; p  < 0.01). Additionally, there was an increased response to SWMT after the procedure. More patients achieved an MRC rating score ≥3 and ≥4 in elbow flexion after surgery. This may be indicative of improved sensory and motor function.

Conclusion  Open fasciotomy and external neurolysis at the medial brachial fascial compartment is an effective treatment for pain when nerve continuity is preserved. These benefits were evident in patients with a prolonged duration elapsed since injury onset.

MANAGEMENT OF BRACHIAL PLEXUS MISSILE INJURIES

SUMMARY – Missile injuries are among the most devastating injuries in general traumatology. Traumatic brachial plexus injuries are the most difficult injuries in peripheral nerve surgery, and most complicated to be surgically treated. Nevertheless, missile wounding is the second most common mechanism of brachial plexus injury. The aim was to evaluate functional recovery after surgical treatment of these injuries. Our series included 68 patients with 202 nerve lesions treated with 207 surgical procedures. Decision on the treatment modality (exploration, neurolysis, graft repair, or combination) was made upon intraoperative finding. Results were analyzed in 60 (88.2%) patients with 173 (85.6%) nerve lesions followed-up for two years. Functional recovery was evaluated according to functional priorities. Satisfactory functional recovery was achieved in 90.4% of cases with neurolysis and 85.7% of cases with nerve grafting. Insufficient functional recovery was verified in ulnar and radial nerve lesions after neurolysis, and in median and radial nerve lesions when graft repair was done. We conclude that the best time for surgery is between two and four months after injury, except for the gunshot wound associated with injury to the surrounding structures, which requires immediate surgical treatment. The results of neurolysis and nerve grafting were similar.

Clinical aspects of ballistic peripheral nerve injury: shrapnel versus gunshot

OBJECTIVES

Ballistic injuries to peripheral nerves pose special challenges in terms of indications, timing and type of surgical intervention. The aim of the present work was to analyze our experience in the surgical treatment of peripheral nerve ballistic injuries with respect to the mechanism of injury (gunshot versus shrapnel), and identify common and dissimilar prognostic factors in both types of injury.

METHODS

This study was conducted on 42 patients totaling 58 nerves. Twenty-two patients (32 nerves) were injured by gunshot and 20 patients (26 nerves) by shrapnel. Median postoperative follow-up was 33 months (range 12 months to 14 years).

RESULTS

Overall postoperative outcome appears to be more favorable for gunshot-wound (GSW) patients than shrapnel-injured patients, especially in terms of neuropathic pain relief (75 % vs. 58 % respectively, p < 0.05). Presence of foreign particles in shrapnel injured patients has a negative impact on the surgical outcome in terms of rate of pain improvement (28 % compared to 67 % in patients with and without foreign particles, respectively). Nerve graft reconstruction, rather than neurolysis, seems to be the more beneficial treatment for shrapnel-induced neuropathic pain (100 % vs. 47 % in improvement rate, respectively). Early surgical intervention (median 2 months after injury) significantly relieved neuropathic pain in 83 % of shrapnel-injured patients compared to 58 % in patients operated later.

CONCLUSIONS

This study suggests that shrapnel injury is more destructive for nerve tissue than gunshot injury. Our impression is that early surgical intervention in shrapnel injuries and split nerve grafting (especially when small fragments are recognized in the nerve) significantly improve the patient's functional activity and quality of life.

Systematic review of the literature on pain in patients with polytrauma including traumatic brain injury

OBJECTIVE

To review the literature addressing the assessment and management of pain in patients with polytraumatic injuries including traumatic brain injury (TBI) and blast-related headache, and to identify patient, clinician and systems factors associated with pain-related outcomes.

DESIGN

Systematic review.

METHODS

We conducted searches in MEDLINE of literature published from 1950 through July 2008. Due to a limited number of studies using controls or comparators, we included observational and rigorous qualitative studies. We systematically rated the quality of systematic reviews, cohort, and case-control design studies.

RESULTS

One systematic review, 93 observational studies, and one qualitative research study met inclusion criteria. The literature search yielded no published studies that assessed measures of pain intensity or pain-related functional interference among patients with cognitive deficits due to TBI, that compared patients with blast-related headache with patients with other types of headache, or that assessed treatments for blast-related headache pain. Studies on the association between TBI severity and pain reported mixed findings. There was limited evidence that the following factors are associated with pain among TBI patients: severity, location, and multiplicity of injuries; insomnia; fatigue; depression; and post-traumatic stress disorder.

CONCLUSIONS

Very little evidence is currently available to guide pain assessment and treatment approaches in patients with polytrauma. Further research employing systematic observational as well as controlled intervention designs is clearly indicated.

From the battlefront: peripheral nerve surgery in modern day warfare

Warfare historically causes a large number of peripheral nerve injuries. During the current global war on terror, an increased use of advanced regional anesthesia techniques appears to have significantly reduced pain syndromes that have been previously reported with missile-induced nerve injuries. Additionally, a new program has been established to develop advanced prosthetic devises that can interface with neural tissue to obtain direct neural control. As this technology matures, the functional restoration gained from these new generation prosthetic devices may exceed that which can be obtained by standard nerve repair techniques.

Governing role of primary afferent drive in increased excitation of spinal nociceptive neurons in a model of sciatic neuropathy

Previously we reported that the cuff model of peripheral neuropathy, in which a 2 mm polyethylene tube is implanted around the sciatic nerve, exhibits aspects of neuropathic pain behavior in rats similar to those in humans and causes robust hyperexcitation of spinal nociceptive dorsal horn neurons. The mechanisms mediating this increased excitation are not known and remain a key unresolved question in models of peripheral neuropathy. In anesthetized adult male Sprague-Dawley rats 2-6 weeks after cuff implantation we found that elevated discharge rate of single lumbar (L(3-4)) wide dynamic range (WDR) neurons persists despite acute spinal transection (T9) but is reversed by local conduction block of the cuff-implanted sciatic nerve; lidocaine applied distal to the cuff (i.e. between the cuff and the cutaneous receptive field) decreased spontaneous baseline discharge of WDR dorsal horn neurons approximately 40% (n=18) and when applied subsequently proximal to the cuff, i.e. between the cuff and the spinal cord, it further reduced spontaneous discharge by approximately 60% (n=19; P<0.05 proximal vs. distal) to a level that was not significantly different from that of naive rats. Furthermore, in cuff-implanted rats WDR neurons (n=5) responded to mechanical cutaneous stimulation with an exaggerated afterdischarge which was reversed entirely by proximal nerve conduction block. These results demonstrate that the hyperexcited state of spinal dorsal horn neurons observed in this model of peripheral neuropathy is not maintained by tonic descending facilitatory mechanisms. Rather, on-going afferent discharges originating from the sciatic nerve distal to, at, and proximal to the cuff maintain the synaptically-mediated gain in discharge of spinal dorsal horn WDR neurons and hyperresponsiveness of these neurons to cutaneous stimulation. Our findings reveal that ectopic afferent activity from multiple regions along peripheral nerves may drive CNS changes and the symptoms of pain associated with peripheral neuropathy.