Applications of Cryoneurolysis in Chronic Pain Management: a Review of the Current Literature

PURPOSE OF REVIEW

The purpose of this review is to evaluate and summarize the literature investigating cryoneurolysis in the treatment of various chronic pain pathologies.

RECENT FINDINGS

There is an increasing amount of interest in the use of cryoneurolysis in chronic pain, and various studies have investigated its use in lumbar facet joint pain, SI joint pain, post-thoracotomy syndrome, temporomandibular joint pain, chronic knee pain, phantom limb pain, neuropathic pain, and abdominal pain. Numerous retrospective studies and a more limited number of prospective, sham-controlled prospective studies suggest the efficacy of cryoneurolysis in managing these chronic pain pathologies with a low complication rate. However, more blinded, controlled, prospective studies comparing cryoneurolysis to other techniques are needed to clarify its relative risks and advantages.

MRI findings correlate with difficult dissection during proximal hamstring repair and with postoperative sciatica

OBJECTIVE

This study examines the correlation between MRI findings and difficult dissection during proximal primary hamstring repair and postoperative sciatica.

MATERIALS AND METHODS

A total of 32 cases of surgically repaired hamstring tendon tears that underwent preoperative and postoperative MRI were divided into sciatica (n = 12) and control (n = 20) groups based on the presence or absence of postoperative sciatica. Cases were scored by two blinded musculoskeletal radiologists for imaging features associated with difficult surgical dissection and the development of subsequent sciatica. Intra- and interrater agreements, as well as correlation of MRI findings with symptoms (odds ratio, OR), were calculated.

RESULTS

On preoperative MRI, diffuse hamstring muscle edema pattern suggestive of active denervation (OR 9.4-13.6), and greater sciatic perineural scar circumference (OR 1.9-2) and length (OR 1.2-1.3) were significantly correlated with both difficult dissection and postoperative sciatica. Preoperatively, a greater number of tendons torn (OR 3.3), greater tear cross-sectional area (CSA, OR 1.03), and increased nerve T2-weighted signal (OR 3.2) and greater perineural scar thickness (OR 1.7) were also associated with difficult dissection, but not postoperative sciatica. On postoperative MRI, hamstring denervation, sciatic nerve tethering to the hamstring tendon, and development of perineural scar and greater perineural scar extent were all significantly correlated with postoperative sciatica.

CONCLUSION

Preoperative hamstring MRI demonstrates findings predictive of difficult sciatic nerve dissection; careful MRI evaluation of the nerve and for the presence and extent of perineural scar is important for preoperative planning. Preoperative and postoperative MRI both depict findings that correlate with postoperative sciatica.

Bone marrow stem cells with or without superparamagnetic iron oxide nanoparticles as a magnetic targeting tool: Which is better in regeneration of neurolysed facial nerve? An experimental study

Aim

This study was performed to evaluate neural regenerative capacities of bone marrow stem cells (BMSCs) with or without superparamagnetic iron oxide nanoparticles (SPIONs) as a magnetic targeting tool after neurolysis of the facial nerve (FN) in albino rats.

Methods

Thirty-eight male albino rats were selected. Two of them were euthanized for normal FN histology assessment. Thirty-six rats were injected with ethanol in the FN nerve for neurolysis induction and assessed one week post-operatively by eye blinking test. Animals were divided into three groups, each containing twelve rats: Group I (positive control) was injected with Dulbecco Modified Eagle's medium (DMEM-F12), group II was injected with BMSCs in DMEM-F12, and group III was injected with BMSCs in DMEM-F12 with poly l-lysine coated SPIONs (0.5 mmol/mL). Monitoring of SPIONs in the rat's body was carried out by MRI. A circular neodymium magnet N52 (0.57 T, 2 × 5 mm) was placed on each rat in group III just below the right ear at the site of surgery to attract SPIONs labeled BMSCs, left in place for 24 h, and then removed. From each group, six rats were euthanized at the end of the 4th and 8th week of treatment, respectively. The right FN trunks were extracted for routine histological examination using H&E stain. Immunohistochemical examination by anti-S100B was performed to characterize the thickness of the myelin sheath formed by the Schwann cells. Ultra-structural examination was performed to study changes in axons, myelin sheaths, and Schwann cells.

Results

Regeneration of nerve fibers, Schwan cells, and myelin sheaths was better in group II than in groups I and III histologically, immunohistochemically, and ultra-structurally.

Conclusion

BMSCs alone could ameliorate FN regeneration better than magnetic targeting treatment using BMSCs labeled with SPIONs.

Functional outcomes of different surgical treatments for common peroneal nerve injuries: a retrospective comparative study

BACKGROUND

This study aims to assess the recovery patterns and factors influencing outcomes in patients with common peroneal nerve (CPN) injury.

METHODS

This retrospective study included 45 patients with CPN injuries treated between 2009 and 2019 in Jing'an District Central Hospital. The surgical interventions were categorized into three groups: neurolysis (group A; n = 34 patients), nerve repair (group B; n = 5 patients) and tendon transfer (group C; n = 6 patients). Preoperative and postoperative sensorimotor functions were evaluated using the British Medical Research Council grading system. The outcome of measures included the numeric rating scale, walking ability, numbness and satisfaction. Receiver operating characteristic (ROC) curve analysis was utilized to determine the optimal time interval between injury and surgery for predicting postoperative foot dorsiflexion function, toe dorsiflexion function, and sensory function.

RESULTS

Surgical interventions led to improvements in foot dorsiflexion strength in all patient groups, enabling most to regain independent walking ability. Group A (underwent neurolysis) had significant sensory function restoration (P < 0.001), and three patients in Group B (underwent nerve repair) had sensory improvements. ROC analysis revealed that the optimal time interval for achieving M3 foot dorsiflexion recovery was 9.5 months, with an area under the curve (AUC) of 0.871 (95% CI = 0.661-1.000, P = 0.040). For M4 foot dorsiflexion recovery, the optimal cut-off was 5.5 months, with an AUC of 0.785 (95% CI = 0.575-0.995, P = 0.020). When using M3 toe dorsiflexion recovery or S4 sensory function recovery as the gold standard, the optimal cut-off remained at 5.5 months, with AUCs of 0.768 (95% CI = 0.582-0.953, P = 0.025) and 0.853 (95% CI = 0.693-1.000, P = 0.001), respectively.

CONCLUSIONS

Our study highlights the importance of early surgical intervention in CPN injury recovery, with optimal outcomes achieved when surgery is performed within 5.5 to 9.5 months post-injury. These findings provide guidance for clinicians in tailoring treatment plans to the specific characteristics and requirements of CPN injury patients.

Review of craniofacial pain syndromes involving the greater occipital nerve: relevant anatomy, clinical findings, and interventional management

Craniofacial pain syndromes exhibit a high prevalence in the general population, with a subset of patients developing chronic pain that significantly impacts their quality of life and results in substantial disabilities. Anatomical and functional assessments of the greater occipital nerve (GON) have unveiled its implication in numerous craniofacial pain syndromes, notably through the trigeminal-cervical convergence complex. The pathophysiological involvement of the greater occipital nerve in craniofacial pain syndromes, coupled with its accessibility, designates it as the primary target for various interventional procedures in managing craniofacial pain syndromes. This educational review aims to describe multiple craniofacial pain syndromes, elucidate the role of GON in their pathophysiology, detail the relevant anatomy of the greater occipital nerve (including specific intervention sites), highlight the role of imaging in diagnosing craniofacial pain syndromes, and discuss various interventional procedures such as nerve infiltration, ablation, neuromodulation techniques, and surgeries. Imaging is essential in managing these patients, whether for diagnostic or therapeutic purposes. The utilization of image guidance has demonstrated an enhancement in reproducibility, as well as technical and clinical outcomes of interventional procedures. Studies have shown that interventional management of craniofacial pain is effective in treating occipital neuralgia, cervicogenic headaches, cluster headaches, trigeminal neuralgia, and chronic migraines, with a reported efficacy of 60-90% over a duration of 1-9 months. Repeated infiltrations, neuromodulation, or ablation may prove effective in selected cases. Therefore, reassessment of treatment response and efficacy during follow-up is imperative to guide further management and explore alternative treatment options. Optimal utilization of imaging, interventional techniques, and a multidisciplinary team, including radiologists, will ensure maximum benefit for these patients.

Compression of the posterior interosseous nerve secondary to a synovial cyst: Case report and review of the literature

INTRODUCTION AND IMPORTANCE

Posterior interosseous nerve syndrome secondary to compression by a synovial cyst at the elbow is a rare and often unrecognized pathology. Early management relies on complete neurolysis to achieve satisfactory functional recovery. Increasing awareness among the orthopedics will help in the early diagnosis of the disease and in the initiation of early and proper treatment.

CASE PRESENTATION

In this article, we report the case of a 32-year-old patient with posterior interosseous nerve syndrome secondary to compression by a synovial cyst of the elbow. Surgical management combined with post-operative rehabilitation resulted in indolence with good functional recovery.

CLINICAL DISCUSSION

Posterior interosseous nerve syndrome secondary to compression by a synovial cyst at the elbow is a rare entity. Anatomically, the deep branch of the radial nerve or posterior interosseous nerve passes through the Fröhse's arch or arch of the supinator muscle at the elbow, then travels between the two heads of this muscle. Several anatomical structures may compress the NIOP. Clinically, it presents as paralysis or paresis of the extensor muscles of the fingers and the abductor muscle of the thumb. Limitation of the ulnar extensor carpi may be responsible for radial deviation of the carpus in some cases. MRI is the radiological examination of choice. Electromyography plays a contributory role in diagnosis prior to surgical exploration. Surgical excision is the treatment of choice. It may be combined with radial neurolysis for better recovery. Progression after surgical treatment is generally favourable.

CONCLUSION

Ignorance of posterior interosseous nerve palsy syndrome frequently leads to misdiagnosis. Early management relies on complete neurolysis to achieve satisfactory functional recovery.

Meralgia paresthetica

Meralgia paresthetica is a common but probably underrecognized syndrome caused by dysfunction of the lateral femoral cutaneous nerve. The diagnosis is based on the patient's description of sensory disturbance, often painful, on the anterolateral aspect of the thigh, with normal strength and reflexes. Sensory nerve conduction studies and somatosensory evoked potentials may be used to support the diagnosis, but both have technical limitations, with low specificity and sensitivity. Risk factors for meralgia paresthetica include obesity, tight clothing, and diabetes mellitus. Some cases are complications of hip or lumbar spine surgery. Most cases are self-limited, but a small proportion of patients remain with refractory and disabling symptoms. Treatment options include medications for neuropathic pain, neurolysis, neurectomy, and radioablation, but controlled trials to compare efficacy are lacking.

A randomized controlled trial comparing conservative versus surgical treatment in patients with foot drop due to peroneal nerve entrapment: results of an internal feasibility pilot study

BACKGROUND

Based on the lack of literature to support any treatment strategy in patients with foot drop due to peroneal nerve entrapment, a prospective study randomizing patients between surgery and conservative treatment is warranted. Since studies comparing surgery to no surgery are often challenging, we first examined the feasibility of such a randomized controlled trial.

METHODS/DESIGN

An internal feasibility pilot study was conducted to assess several aspects of process, resource, management, and scientific feasibility. The main objective was the assessment of the recruitment rate. The criterion to embark on a full study was the recruitment of at least 14 patients in 6 participating centers within 6 months. Cross-over rate, blinding measures, training strategies, and trial assessments were evaluated. The trial was entirely funded by the KCE Trials public funding program of the Belgian Health Care Knowledge Centre (ID KCE19-1232).

RESULTS

The initial duration was prolonged due to the COVID-19 pandemic. Between April 2021 and October 2022, we included 19 patients of which 15 were randomized. Fourteen patients were treated as randomized. One drop-out occurred after randomization, prior to surgery. We did not document any cross-over or accidental unblinding. Training strategies were successful. Patients perceived the quality of life questionnaire as the least relevant assessment. Assessment of ankle dorsiflexion range of motion was prone to interobserver variability. All other trial assessments were adequate.

DISCUSSION

Recruitment of the anticipated 14 patients was feasible although slower than expected. The Short-Form Health Survey (SF-36) and assessment of ankle dorsiflexion range of motion will no longer be included in the full-scale FOOTDROP trial.

CONCLUSION

The FOOTDROP study is feasible.

TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT04695834 . Registered 4 January 2021.

Variations of the obturator nerve and implications in obturator nerve entrapment treatment: an anatomical study

INTRODUCTION

Obturator nerve entrapment or idiopathic obturator neuralgia is an unfamiliar pathology for many physicians which can lead to diagnostic errancy. This study aims to identify the potential compression areas of the obturator nerve to improve therapeutic management.

MATERIAL AND METHODS

18 anatomical dissections of lower limbs from 9 anatomical cadavers were performed. Endopelvic and exopelvic surgical approaches were utilized to study the anatomical variations of the nerve and to identify areas of entrapment.

RESULTS

On 7 limbs, the posterior branch of the obturator nerve passed through the external obturator muscle. A fascia between the adductor brevis and longus muscles was present in 9 of the 18 limbs. The anterior branch of the obturator nerve was highly adherent to the fascia in 6 cases. In 3 limbs, the medial femoral circumflex artery was in close connection with the posterior branch of the nerve.

CONCLUSION

Idiopathic obturator neuropathy remains a difficult diagnosis. Our cadaveric study did not allow us to formally identify one or more potential anatomical entrapment zones. However, it allowed the identification of zones at risk. A clinical study with staged analgesic blocks would be necessary to identify an anatomical area of compression and would allow targeted surgical neurolysis.

Unusual entrapment symptomatology treated in 115 cases by neurolysis of the common fibular nerve at the fibular head combined with neurolysis of the posterior tibial nerve at the tarsal tunnel

INTRODUCTION

Entrapment of the common fibular nerve (CFN) at the head of the fibula and entrapment of the posterior tibial nerve (PTN) at the tarsal tunnel are the most common nerve entrapment syndromes in the lower limb. Our aim was to study the results of combined neurolysis of the CFN and PTN for chronic lower limb pain. We hypothesized that combined neurolysis allowed a reduction of this chronic pain.

MATERIAL AND METHOD

This bi-centric retrospective study took place from January 2015 to November 2018, with a single senior surgeon. The inclusion criteria were all patients operated on for an idiopathic entrapment syndrome with neurolysis of the PTN at the tarsal tunnel, combined with neurolysis of the CFN at the head of the fibula. The primary endpoint was the pain evolution assessed on a numerical analogue scale (NAS) preoperatively and postoperatively on D+21, and at the last follow-up. The secondary endpoint was to determine the prognostic factors on the clinical outcome of neurolysis.

RESULTS

One hundred and fifteen neurolysis were included, comprising 64 women and 38 men with a mean age of 57±17.6 years. The preoperative pain (NAS0) was evaluated at 6±2.4 points. At D+21 postoperatively, there was a significant reduction in pain (NASD+21: 3±2.6 points, p<0.01). Similarly, at the last follow-up (with a mean follow-up of 37±8.4 months), there was a significant reduction in pain (NASLFU: 2±2.5, p<0.01). A history of systemic inflammatory disease was the only factor associated with a less significant decrease in pain at D+21, according to a multivariate analysis (p<0.01). There were 14 complications (12%) not requiring revision surgery.

CONCLUSION

This study is the first to demonstrate the efficacy of combined neurolysis of the CFN at the head of the fibula and the PTN at the tarsal tunnel, in the treatment of idiopathic nerve entrapment syndrome of the lower limb.

LEVEL OF EVIDENCE

IV; Retrospective comparative study.

Bilateral Post-traumatic Brachial Plexus Injury in an Adult: A Note on the Probable Mechanism of Injury

Bilateral brachial plexus injury is rare following a motor vehicle accident in an adult. We report a 35-year-old man with a bilateral brachial plexus injury. Explaining the mechanism of such an injury is essential to prognosticate the outcome. Fall from the bike, and the position determines the mechanism. The head-shoulder hitting the surface has an avulsion injury (ipsilateral), and the recoiling effect causes traction injury to the contralateral side. Our case had a C5,6 avulsion injury on the right side (ipsilateral) and a C5,6 traction injury (contralateral) to his left side. Surgical exploration and distal nerve transfers were done on the right side. The patient improved his shoulder and elbow function of grade 3, neurolysis of the brachial plexus was done on the left side, and the recovery was complete at 12 months of follow-up.

Diagnosis and treatment of meralgia paresthetica between 2005 and 2018: a national cohort study

The prevalence of meralgia paresthetica (MP), which is caused by compression of the lateral femoral cutaneous nerve (LFCN), has been increasing over recent decades. Since guidelines and large-scale studies are lacking, there are substantial regional differences in diagnostics and management in MP care. Our study aims to report on current diagnostic and therapeutic strategies as well as time trends in clinical MP management in Germany. Patients hospitalized in Germany between January 1, 2005, and December 31, 2018, with MP as their primary diagnosis were identified using the International Classification of Disease (ICD-10) code G57.1 and standardized operations and procedures codes (OPS). A total of 5828 patients with MP were included. The rate of imaging studies increased from 44% in 2005 to 79% in 2018 (p < 0.001) and that of non-imaging diagnostic studies from 70 to 93% (p < 0.001). Among non-imaging diagnostics, the rates of evoked potentials and neurography increased from 20%/16% in 2005 to 36%/23% in 2018 (p < 0.001, respectively). Rates of surgical procedures for MP decreased from 53 to 37% (p < 0.001), while rates of non-surgical procedures increased from 23 to 30% (p < 0.001). The most frequent surgical interventions were decompressive procedures at a mean annual rate of 29% (± 5) throughout the study period, compared to a mean annual rate of 5% (± 2) for nerve transection procedures. Between 2005 and 2018, in-hospital MP care in Germany underwent significant changes. The rates of imaging, evoked potentials, neurography, and non-surgical management increased. The decompression of the LFCN was substantially more frequent than that of the LFCN transection, yet both types of intervention showed a substantial decrease in in-hospital prevalence over time.

Meralgia Paresthetica Review: Update on Presentation, Pathophysiology, and Treatment

Purpose of Review

Meralgia paresthetica (MP) is a condition characterized by paresthesias, neuropathic pain, and alterations in sensorium of the anterolateral thigh secondary to impingement of the lateral femoral cutaneous nerve (LFCN). MP is generally diagnosed by clinical history and is often a diagnosis of exclusion. When diagnosis remains a challenge, diagnostic modalities such as ultrasound, MRI, electromyography, and nerve conduction studies have been utilized as an adjunct. This review summarizes the most recent medical literature regarding MP, its pathophysiology, presentation, and current treatment options.

Recent Findings

Treatment options for patients with MP range from lifestyle modifications and conservative management to surgical procedures. Initial management is often conservative with symptoms managed with medications. When conservative management fails, the next step is regional blocks followed by surgical management. The conflicting data for treatment options for MP highlight how the evidence available does not point to a single approach that's universally effective for treating all patients with MP.

Summary

Despite the apparent success at treating MP with regional blocks and surgical interventions, much remains to be known about the dosing, frequency, and optimal interventions due to the inconclusive results of current studies. Further research including randomized controlled trials are needed to better understand the most optimal treatment options for MP including studies with a larger number of participants.

Conservative versus surgical treatment of foot drop in peroneal nerve entrapment: rationale and design of a prospective, multi-centre, randomized parallel-group controlled trial

BACKGROUND

High-quality evidence is lacking to support one treatment strategy over another in patients with foot drop due to peroneal nerve entrapment. This leads to strong variation in daily practice.

METHODS/DESIGN

The FOOTDROP (Follow-up and Outcome of Operative Treatment with Decompressive Release Of The Peroneal nerve) trial is a randomized, multi-centre study in which patients with peroneal nerve entrapment and persistent foot drop, despite initial conservative treatment, will be randomized 10 (± 4) weeks after onset between non-invasive treatment and surgical decompression. The primary endpoint is the difference in distance covered during the 6-min walk test between randomization and 9 months later. Time to recovery is the key secondary endpoint. Other secondary outcome measures encompass ankle dorsiflexion strength (MRC score and isometric dynamometry), gait assessment (10-m walk test, functional ambulation categories, Stanmore questionnaire), patient-reported outcome measures (EQ5D-5L), surgical complications, neurological deficits (sensory changes, motor scores for ankle eversion and hallux extension), health economic assessment (WPAI) and electrodiagnostic assessment.

DISCUSSION

The results of this randomized trial may elucidate the role of surgical decompression of the peroneal nerve and aid in clinical decision-making.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04695834. Registered on 4 January 2021.

EUS-guided celiac plexus neurolysis for pancreas cancer - Finally established or still under review?

Patients with pancreas cancer must deal frequently with intractable and refractory pain. Endoscopic ultrasound guided-celiac plexus neurolysis (EUS-CPN) has been the most studied and used therapeutic technique aimed to destroy the pain fibres that allow the pancreas to communicate with the central nervous system. A neurolytic agent, most commonly ethanol, is optimally spread around the celiac axis in order to reduce pain and mitigate narcotic requirements. This can be performed early to prevent the spiral of pain and medication use, or more historically as salvage therapy. Different techniques to best administer the ethanol for effective EUS-CPN are still being debated. New EUS-guided injection techniques with radiofrequency, radioactive, and/or chemotherapeutic agents need more study.

Neurolysis for analgesia following pectus repair in a national cohort

INTRODUCTION

Pectus excavatum and pectus carinatum are the most common chest wall deformities of childhood. Surgical repair can be complicated by post-operative analgesic challenges. Thoracic epidural analgesia, patient-controlled analgesia, and multimodal pain control are among the most common strategies. We sought to define the current utilization of intraoperative thoracic neurolysis, hypothesizing that this would minimize length of stay (LOS) and post-operative narcotic use with relatively higher proportion of non-narcotic post-operative analgesia.

METHODS

We performed a retrospective review of the Pediatric Health Information System (PHIS) database between 2017 and 2020. We first identified patients who underwent a pectus repair via ICD-10-PCS codes. We used ICD-10-PCS codes 01580ZZ and 01584ZZ to identify those patients who underwent concomitant thoracic neurolysis. Statistical analyses were performed using R; p value less than 0.05 was considered significant.

RESULTS

We identified 2979 patients who underwent a pectus repair. 184 underwent a concomitant thoracic nerve destruction procedure (6.7%); 13 were performed in 2017 (2.01%), 76 in 2018 (10.7%), and 84 in 2019 (9.6%). LOS was shorter in those patients who underwent neurolysis (mean=2.55 vs 3.73 days, SD=1.33 vs 1.78 days, p<0.001). There were fewer post-operative ICU admissions in neurolysis patients (3/184 vs. 193/2795, p = 0.003). The cost of procedures that included a neurolysis were higher, though not significantly so (mean=$24,885.64 vs $22,200.59).

CONCLUSION

Thoracic neurolysis may be a useful analgesic strategy, expediating post-operative discharge and potentially obviating the need for intensive care. Further larger-scale prospective trials should be considered to further elucidate the role of this analgesia method.

LEVEL OF EVIDENCE

Level III.

Clinical outcomes following neurolysis and porcine collagen extracellular matrix wrapping of scarred nerves in revision carpal tunnel decompression

Scar tether after primary nerve decompression can impair physiological nerve glide and vascularity of the nerve. Revision decompression in the setting of neurostenalgia should address the scarred mesoneurium in order to prevent further entrapment and tether. This study reports on the clinical outcomes of 12 patients with neurostenalgia following carpal tunnel decompression (CTD), treated with revision CTD and a porcine submucosa extracellular matrix nerve wrap (PECM) (Axoguard® nerve protector, Axogen Inc., Alachua, FL). Eleven patients had one primary decompression procedure prior to revision surgery; one patient previously had two operations for CTD. There was a significant reduction in visual analogue pain scores (VAS) and improvement in patients' satisfaction rating and symptom resolution. Patient-reported outcome measures were recorded using the Impact of Hand Nerve Disorders (I-HaND) Scale (Version 2), which demonstrated a significant reduction in hand disability. There were no complications attributable to the procedure and no re-revision procedures necessary at the latest follow-up.

Nerve Injury and Regeneration after Neurolysis: Ethanol Combined with Iodine-125 Radioactive Seed versus Ethanol Alone in Rabbits

PURPOSE

This study aimed to prove the hypothesis that neurolysis based on ethanol injection in combination with iodine-125 (¹²⁵I) radioactive seed implantation could prolong nerve regeneration time compared with ethanol injection alone. Moreover, we assessed the grade of nerve injury using both methods.

MATERIALS AND METHODS

Twenty female rabbits (mean 2.8 ± 0.2 kg) were randomly assigned to group A (neurolysis of the left brachial plexus nerve based on ethanol injection in combination with ¹²⁵I radioactive seed implantation, n=10) and group B (neurolysis using ethanol injection alone, n=10). The right brachial plexus nerve was used as a blank control. Injury and regeneration of the brachial plexus nerve were analyzed using electromyography (EMG). Statistical tests were performed using the Mann-Whitney U test and repeated-measures analysis of variance. The results were verified with histopathological examinations.

RESULTS

The overall postprocedural amplitude was significantly lower in group A than in group B (P=0.01), particularly in the second month after the procedure (P=0.036). However, no statistical difference in latency was observed between the two groups (P=0.103). Histopathological examination of both groups revealed Sunderland's third-degree peripheral nerve injury (PNI), mainly characterized by axon disintegration. The degree of nerve regeneration was significantly lower in group A than in group B.

CONCLUSION

Neurolysis based on ethanol injection in combination with ¹²⁵I radioactive seed implantation can prolong the time of nerve regeneration compared to ethanol injection alone, although both methods resulted in Sunderland's third-degree PNI.

Operative treatment options for Morton's neuroma other than neurectomy - a systematic review

BACKGROUND

The effectiveness of operative treatments other than neurectomy for Morton's neuroma remains debatable despite several reported studies. This review aimed to evaluate the effects of operative treatments for Morton's neuroma other than neurectomy using an algorithmic approach and a structured critical framework to assess the methodological quality of reported studies.

METHODS

Several electronic databases were searched for articles published until August 2021 that evaluated the outcomes of operative treatments other than neurectomy in patients diagnosed with Morton's neuroma. Data searches, extraction, analysis, and quality assessments were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and the clinical outcomes were evaluated using objective, subjective, and negative outcomes; complications; and reoperation rate and type.

RESULTS

After reviewing 11,213 studies, 22 studies were finally included. Although a number of studies with high level of evidence are limited, we divided them according to four categories: (1) neurolysis with or without nerve transposition, (2) minimally invasive nerve decompression, (3) metatarsal osteotomy, and (4) additional procedures after nerve transection or neurectomy. All categories showed reliable outcomes except minimally invasive nerve decompression. The proportion of postoperative neurogenic symptoms was lower with neurolysis than with neurectomy.

CONCLUSION

Whether the alternative procedures were superior to neurectomy remains unclear as the number of good quality studies was limited. The proportion of postoperative neurogenic symptoms was lower with neurolysis than with neurectomy. Furthermore, performing simultaneous dorsal transposition of the nerve along with neurolysis is more recommended than neurolysis alone. Surgeons should be more careful with minimally invasive deep transverse intermetatarsal ligament release and metatarsal shortening osteotomy as their effectiveness remains inconclusive. Finally, we strongly recommend performing intramuscular embedding or intermuscular transposition of the nerve cutting end if neurectomy or nerve transection is inevitable.

LEVEL OF EVIDENCE

Level III, systematic review.

Surgical Treatment of Foot Drop: Patient Evaluation and Peripheral Nerve Treatment Options

Foot drop is a common clinical condition which may substantially impact physical function and health-related quality of life. The etiologies of foot drop are diverse and a detailed history and physical examination are essential in understanding the underlying pathophysiology and capacity for spontaneous recovery. Patients presenting with acute foot drop or those without significant spontaneous recovery of motor deficits may be candidates for surgical intervention. The timing, mechanism, and severity of neural injury resulting in foot drop influence the selection of the most appropriate peripheral nerve surgery, which may include direct nerve repair, neurolysis, nerve grafting, or nerve transfer.

Splanchnic nerve neurolysis via the transdiscal approach under fluoroscopic guidance: a retrospective study

Background

Neurolytic celiac plexus block (NCPB) is a typical treatment for severe epigastric cancer pain, but the therapeutic effect is often affected by the variation of local anatomical structures induced by the tumor. Greater and lesser splanchnic nerve neurolysis (SNN) had similar effects to the NCPB, and was recently performed with a paravertebral approach under the image guidance, or with the transdiscal approach under the guidance of computed tomography. This study observed the feasibility and safety of SNN via a transdiscal approach under fluoroscopic guidance.

Methods

The follow-up records of 34 patients with epigastric cancer pain who underwent the splanchnic nerve block via the T11-12 transdiscal approach under fluoroscopic guidance were investigated retrospectively. The numerical rating scale (NRS), the patient satisfaction scale (PSS) and quality of life (QOL) of the patient, the dose of morphine consumed, and the occurrence and severity of adverse events were recorded preoperatively and 1 day, 1 week, 1 month, and 2 months after surgery.

Results

Compared with the preoperative scores, the NRS scores and daily morphine consumption decreased and the QOL and PSS scores increased at each postoperative time point (P < 0.001). No patients experienced serious complications.

Conclusions

SNN via the transdiscal approach under flouroscopic guidance was an effective, safe, and easy operation for epigastric cancer pain, with fewer complications.

Direct intraoperative versus percutaneous computed tomographyguided celiac plexus neurolysis in non-resectable pancreatic cancer: A randomized, controlled, non-inferiority study

BACKGROUND

Celiac plexus neurolysis (CPN) has been used to control pancreatic cancer (PC) pain, up to our knowledge, there is no study compared intraoperative CPN and computed tomography (CT)-guided techniques.

OBJECTIVES

To compare the effects of intraoperative and CT-guided CPN in unresectable PC on pain intensity and analgesic requirements.

METHODS

A total of 90 patients were enrolled in this prospective, randomized, open label, controlled, non-inferiority study, 20 patients were excluded or lost to follow up. The patients were randomly allocated to either intraoperative or CT-guided CPN group. A mixture of 20 mL ethanol 90%, 100 mg lignocaine and 5 mg dexamethasone was infused on each side of the aorta in both groups. Visual analogue score (VAS) and oral daily tramadol consumption were recorded at day 7, 14, 30, 60, 120 and 180 days after intervention. Occurrence of any intervention related complications were reported.

RESULTS

Median VAS was similar in both intraoperative and CT-guided CPN groups from day 7 up to 180 days after intervention. The median daily analgesic consumption of oral tramadol (mg) was comparable in both intraoperative and CT-guided CPN groups after intervention at day 7 (50 versus 50), day14 (50 versus 50), day 30 (50 versus 50), day 60 (50 versus 50), day 120 (100 versus 75) and day 180 (100 versus 100). The incidence of diarrhea, vomiting, hypotension and back pain was similar in both groups.

CONCLUSION

Intraoperative CPN is non-inferior to CT-guided CPN as both techniques were similarly associated with reduced pain severity and analgesics requirements.

Median arcuate ligament syndrome - Current state of management

Symptomatic celiac artery compression syndrome (CACS) or median arcuate ligament syndrome (MALS) is a controversial diagnosis that should be considered in patients with chronic abdominal pain of unknown etiology despite an extensive medical evaluation. Once suspected, patients should undergo mesenteric duplex ultrasound. Diagnosis is confirmed with elevated celiac artery velocities which normalize with deep inspiration followed by CT angiogram showing the typical "J-hook" conformation of the celiac artery. Patients should then undergo evaluation by a multi-disciplinary team to appropriately select and prepare patients for potential surgical treatment. Surgical options include release of the median arcuate ligament, with or without neurolysis of the celiac nerve plexus, and with or without concomitant revascularization procedures. Approaches can be open, laparoscopic, or robotic. Surgical treatment has an overall success rate of 70-80% with patients reporting improved abdominal pain and quality of life. Post-operatively, patients can have persistent or recurrent abdominal pain and should undergo re-evaluation for possible need for a revascularization procedure for stenosis of the celiac artery or celiac plexus block if the celiac artery flow is normalized. Additionally, some patients will have persistent pain consistent with functional gastrointestinal disorder (FGID) that will then require medical management. Psychiatric comorbidities have been identified as a predisposing factor that may predict poorer outcomes, and there are preliminary findings suggesting that patients with dysautonomia diagnoses may have worse outcomes as well.

Long Time Efficacy and Safety of Microvascular Decompression Combined with Internal Neurolysis for Recurrent Trigeminal Neuralgia

Objective

To explore the clinical efficacy and safety of microvascular decompression (MVD) combined with internal neurolysis (IN) in the treatment of recurrent trigeminal neuralgia (TN) after MVD.

Methods

Sixty-four patients with recurrent TN admitted to the hospital from January 2014 to December 2017 were divided into two groups according to the surgical method. Twenty-nine patients, admitted from January 2014 to December 2015, were treated with MVD alone, whereas 35 admitted from January 2016 to December 2017 were treated with MVD+IN. The postoperative efficacy, complications, and pain recurrence rate of the two groups were analyzed.

Results

The efficacy of the MVD+IN and MVD groups were 88.6% and 86.2%, and the cure rates were 77.1% and 65.5% respectively. There was no statistically significant difference between the two groups (p>0.05). The cure rate (83.3%) of patients in the MVD+IN group, who were only found thickened arachnoid adhesions during the operation that could not be fully released, was significantly higher than that of the MVD group (30.0%) (p<0.05), while the efficacy (91.7% vs. 70%) of the two groups was not statistically different (p>0.05). For patients whose arachnoid adhesions were completely released, there had no significant difference (p>0.05) in the efficacy (87% vs. 94.7%) and recurrence rate (5.0% vs. 11.1%). The incidence of postoperative facial numbness (88.6%) in the MVD+IN group was higher than that in the MVD group (10.3%) (p<0.01). The long-term incidence of facial numbness was not statistically significant (p>0.05). In the 18–36 months follow-up, the recurrence rate of patients in the MVD+IN group (9.7%) and in the MVD group (16%) were not statistically different (p>0.05).

Conclusion

A retrospective comparison of patients with recurrent TN showed that both MVD and MVD combined with IN can effectively treat recurrent TN. Compared with MVD alone, MVD combined with IN can effectively improve the pain cure rate of patients with recurrent TN who have only severe arachnoid adhesions. The combination does not increase the incidence of long-term facial numbness and other complications.

External Neurolysis in Microvascular Decompression for Magnetic Resonance Imaging-Negative Idiopathic Trigeminal Neuralgia

OBJECTIVE

Internal neurolysis has been proposed as an alternative to microvascular decompression in patients with idiopathic trigeminal neuralgia (TN) in whom neurovascular compression is not confirmed by magnetic resonance imaging (MRI). External neurolysis, which straightens and realigns the trigeminal nerve root axis by dissecting the arachnoid membranes around the nerve, was reported 20 years ago in the context of so-called negative exploration when MRI did not confirm the absence of the offending vessel, but is not currently used.

METHODS

External neurolysis was performed in 4 patients with idiopathic TN with typical evoked neuralgic pain despite the absence of suspected offending vessels on MRI. The surgical findings that caused TN were summarized and the outcomes were evaluated using the Barrow Neurological Institute Pain Intensity Scale (BNI-PS).

RESULTS

Tethering and distortion of the nerve root by surrounding arachnoid membranes were commonly found. All 4 patients showed complete pain relief immediately after surgery. During the follow-up period of 26.5 ± 16.92 months (±standard deviation), 3 of 4 patients had no pain (score I, BNI-PS). One patient received a score of IIIa on the BNI-PS assessment. There was no instance of recurrence or side effects associated with the surgery.

CONCLUSIONS

Idiopathic TN can be induced by individual variation of the surrounding inner arachnoid membranes supporting the trigeminal nerve root, and the condition cannot be identified by MRI. Intradural external neurolysis may be considered an effective treatment for MRI-negative idiopathic TN.