Iatrogenic Nerve Injuries

Paralysis of the trapezius muscle: evaluation and surgical management

Background

Paralysis of the trapezius muscle most commonly results from iatrogenic injury to the spinal accessory nerve.

Methods

The clinical presentation and physical examination findings of trapezius palsy have been well characterized, but unfortunately the diagnosis of this condition is oftentimes missed or delayed, sometimes leading to unnecessary surgery on the rotator cuff or tendon of the long head of the biceps.

Results

The diagnosis can be confirmed using electromyography with nerve conduction studies. Although nonoperative treatment may help some patients with temporary neurapraxia of the spinal accessory nerve, nerve repair with or without nerve grafting should be performed soon for patients suspected of a nerve transection. Nerve transfers can be considered within the first year after the injury when nerve repair and grafting cannot be completed. For chronic trapezius palsy, transfer of the levator scapulae and rhomboids has been refined and represents a very successful surgical procedure. Rarely, scapulothoracic arthrodesis is considered for individuals with failed tendon transfers or multiple nerve involvement.

Conclusion

Trapezius palsy is oftentimes missed. An accurate diagnosis allows consideration of various treatment modalities that have been reported to provide good outcomes for properly selected patients.

NaV1.7 targeted fluorescence imaging agents for nerve identification during intraoperative procedures

Surgeries and trauma result in traumatic and iatrogenic nerve damage that can result in a debilitating condition that approximately affects 189 million individuals worldwide. The risk of nerve injury during oncologic surgery is increased due to tumors displacing normal nerve location, blood turbidity, and past surgical procedures, which complicate even an experienced surgeon's ability to precisely locate vital nerves. Unfortunately, there is a glaring absence of contrast agents to assist surgeons in safeguarding vital nerves. To address this unmet clinical need, we leveraged the abundant expression of the voltage-gated sodium channel 1.7 (NaV1.7) as an intraoperative marker to access peripheral nerves in vivo, and visualized nerves for surgical guidance using a fluorescently-tagged version of a potent NaV1.7-targeted peptide, Tsp1a, derived from a Peruvian tarantula. We characterized the expression of NaV1.7 in sensory and motor peripheral nerves across mouse, primate, and human specimens and demonstrated universal expression. We synthesized and characterized a total of 10 fluorescently labeled Tsp1a-peptide conjugates to delineate nerves. We tested the ability of these peptide-conjugates to specifically accumulate in mouse nerves with a high signal-to-noise ratio in vivo. Using the best-performing candidate, Tsp1a-IR800, we performed thyroidectomies in non-human primates and demonstrated successful demarcation of the recurrent laryngeal and vagus nerves, which are commonly subjected to irreversible damage. The ability of Tsp1a to enhance nerve contrast during surgery provides opportunities to minimize nerve damage and revolutionize standards of care across various surgical specialties.

Femoral and obturator neuropathies

The femoral and obturator nerves both arise from the L2, L3, and L4 spinal nerve roots and descend into the pelvis before emerging in the lower limbs. The femoral nerve's primary function is knee extension and hip flexion, along with some sensory innervation to the leg. The obturator nerve's primary function is thigh adduction and sensory innervation to a small area of the medial thigh. Each may be injured by a variety of potential causes, many of them iatrogenic. Here, we review the anatomy of the femoral and obturator nerves and the clinical features and potential etiologies of femoral and obturator neuropathies. Their necessary investigations, including electrodiagnostic studies and imaging, their prognosis, and potential treatments, are discussed in this chapter.

Infrared neural stimulation markedly enhances nerve functionality assessment during nerve monitoring

In surgical procedures where the risk of accidental nerve damage is prevalent, surgeons commonly use electrical stimulation (ES) during intraoperative nerve monitoring (IONM) to assess a nerve's functional integrity. ES, however, is subject to off-target stimulation and stimulation artifacts disguising the true functionality of the specific target and complicating interpretation. Lacking a stimulation artifact and having a higher degree of spatial specificity, infrared neural stimulation (INS) has the potential to improve upon clinical ES for IONM. Here, we present a direct comparison between clinical ES and INS for IONM performance in an in vivo rat model. The sensitivity of INS surpasses that of ES in detecting partial forms of damage while maintaining a comparable specificity and sensitivity to more complete forms. Without loss in performance, INS is readily compatible with existing clinical nerve monitoring systems. These findings underscore the clinical potential of INS to improve IONM and surgical outcomes.

The role of hyperbaric oxygen therapy in the management of perioperative peripheral nerve injury: a scoping review of the literature

Background/importance

Peripheral nerve injury is an uncommon but potentially catastrophic complication of anesthesia and surgery, for which there are limited effective treatment options. Hyperbaric oxygen therapy is a unique medical intervention which improves tissue oxygen delivery and reduces ischemia via exposure to oxygen at supra-atmospheric partial pressures. While the application of hyperbaric oxygen therapy has been evidenced for other medical conditions involving relative tissue ischemia, its role in the management of peripheral nerve injury remains unclear.

Objective

This scoping review seeks to characterize rehabilitative outcomes when hyperbaric oxygen therapy is applied as an adjunct therapy in the treatment of perioperative peripheral nerve injury.

Evidence review

The review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines for scoping reviews, using a systematic screening and extraction process. The search included articles published from database inception until June 11, 2022, which reported clinical outcomes (in both human and non-human models) of peripheral nerve injury treated with hyperbaric oxygen therapy.

Findings

A total of 51 studies were included in the narrative synthesis. These consisted of animal (40) and human studies (11) treating peripheral nerve injury due to various physiological insults. Hyperbaric oxygen therapy protocols were highly heterogenous and applied at both early and late intervals relative to the time of peripheral nerve injury. Overall, hyperbaric oxygen therapy was reported as beneficial in 88% (45/51) of included studies (82% of human studies and 90% of animal studies), improving nerve regeneration and/or time to recovery with no reported major adverse events.

Conclusions

Existing data suggest that hyperbaric oxygen therapy is a promising intervention in the management of perioperative peripheral nerve injury, in which tissue ischemia is the most common underlying mechanism of injury, neurological deficits are severe, and treatment options are sparse. This positive signal should be further investigated in prospective randomized clinical trials.

DXM-TransFuse U-net: Dual cross-modal transformer fusion U-net for automated nerve identification

Accurate nerve identification is critical during surgical procedures to prevent damage to nerve tissues. Nerve injury can cause long-term adverse effects for patients, as well as financial overburden. Birefringence imaging is a noninvasive technique derived from polarized images that have successfully identified nerves that can assist during intraoperative surgery. Furthermore, birefringence images can be processed under 20 ms with a GPGPU implementation, making it a viable image modality option for real-time processing. In this study, we first comprehensively investigate the usage of birefringence images combined with deep learning, which can automatically detect nerves with gains upwards of 14% over its color image-based (RGB) counterparts on the F2 score. Additionally, we develop a deep learning network framework using the U-Net architecture with a Transformer based fusion module at the bottleneck that leverages both birefringence and RGB modalities. The dual-modality framework achieves 76.12 on the F2 score, a gain of 19.6 % over single-modality networks using only RGB images. By leveraging and extracting the feature maps of each modality independently and using each modality's information for cross-modal interactions, we aim to provide a solution that would further increase the effectiveness of imaging systems for enabling noninvasive intraoperative nerve identification.

Total, gender- and age-specific incidence rates of upper extremity nerve injuries in Finland

The aim of this study was to describe the epidemiology of nerve injuries of the upper extremity in the whole population of Finland (1998-2016). Data based on diagnosis codes were obtained from the Care Register for Health Care, including cases of median, radial, ulnar, musculocutaneous, axillary and digital nerves. Age- and gender-specific incidence rates, both crude and standardized (for the European normal population in 2011), were calculated. Our study included 13,440 patients with upper extremity nerve injury. The mean standardized annual incidence rate of any upper extremity nerve injury was 18.18 among men and 8.15 among women per 100,000 person-years over the study period. The incidence peaked among men at working age. Nerve injuries occurred most commonly in the fingers and thumb, with 5532 cases and mean standardized incidence rates per 100,000 person-years of 7.84 among men and 2.95 among women. The annual incidence did not change significantly over the study period.Level of evidence: III.

An overlooked nerve in neuropathies associated with intragluteal injections: the posterior femoral cutaneous nerve

OBJECTIVE

The aim of this study was to investigate the frequency of posterior femoral cutaneous nerve (PFCN) lesions in patients referred to the electrophysiology laboratory with an initial diagnosis of sciatic nerve lesion following injection, and to create awareness that PFCN lesions can occur following intramuscular injections administered to the gluteal region.

METHODS

Fifty-seven patients who were referred to the electrophysiology laboratory because of injection neuropathy were identified from the hospital records. In addition to the routine electrophysiological examination, PFCN sensory conduction study was performed according to the technique of Dumitru and Nelson. The scores of the Hospital Anxiety and Depression Scale (HADS) and the Leeds Assessment of Neuropathic Symptoms and Signs Pain Scale were recorded for all participants.

RESULTS

Of the 21 participants who agreed to participate in the study, 2 patients were diagnosed with PFCN lesions, one of them had isolated complete PFCN lesion, and another had it accompanied by sciatic nerve lesion. Patients with PFCN lesions had a lower body mass index and a higher HADS score than patients with sciatic nerve lesions (p = 0.01, p = 0.04, respectively).

CONCLUSIONS

As correct diagnosis is the priority starting point for successful treatment, clinicians should plan examinations taking into consideration the fact that PFCN lesions can occur following gluteal region injection.

Frequency of Type-1 Berrettini's Connection in a Neurophysiology Laboratory

Objective  This study aims to estimate the frequency of Berrettini's ulnar-median nerves communication in a neurophysiology laboratory.

Materials and Methods  A total of 358 hands belonging to patients, both sexes, median age of 58 years, was studied. Antidromic sensory nerve conduction studies of the ulnar nerves, registered in digits III and IV were performed in search of the ulnar-median communication. A Berrettini's percentage was calculated in each communication: [(amplitude SAP digit III/amplitude SAP digit IV) × 100].

Results  Ulnar-median nerves communication (Berrettini's branch) was found in 37 hands (10.95%), with a female gender predominance. Bilaterality percentage was low (1.78%). Most communications encountered had a Berretini's percentage between 11 and 50%. Some of them exceeded 100%.

Conclusions  Electromyographers should routinely search for this nerve communication, especially in those patients undergoing carpal tunnel syndrome or Dupuytren's contracture surgeries.

Iatrogenic peripheral nerve injuries - Common causes and treatment: A retrospective single-center cohort study

BACKGROUND

Iatrogenic nerve injuries can result from surgical damage. Thus, physicians should be aware of the risk factors and procedures that need to be followed in such patients. The purpose of this study was to examine data pertaining to patients with known iatrogenic nerve injuries and to elucidate the detailed causes of these injuries, the affected nerves, and the type of surgical procedures for treatment.

METHODS

This retrospective study included 232 consecutive patients who underwent surgical treatment for peripheral nerve palsy or nerve injury between 2006 and 2017 at our hospital. Among the 232 patients investigated, we identified 51 cases with iatrogenic nerve injuries (23 women and 28 men; mean age, 51.3 years). Among the 51 patients, 45 were referred from other hospitals, and the remaining were from our hospital. Data were summarized using descriptive statistics.

RESULTS

Direct surgical damage occurred in 94% (48/51) of patients with iatrogenic nerve injuries. Such injuries mostly developed after surgery for bone fractures (33%), resection of soft tissue tumors (22%), and carpal tunnel release procedures (20%). The nerves most commonly affected in such procedures are the radial nerve (26%), median nerve (24%), and ulnar nerve (17%). The median interval of referral to our hospital after nerve injury was 5.1 months. The median interval of surgery to correct the injury was 7 months. Surgeries to correct iatrogenic nerve injuries performed at our hospital included neurolysis (55%), nerve grafts (29%), direct suture procedures (10%), and tendon transfers (6%).

CONCLUSIONS

We believe that wide dissemination of the results obtained in this study will reduce the incidence of iatrogenic peripheral nerve injuries and increase the speed of referrals to specialized centers.

Iatrogenic peripheral nerve injury: a guide to management for the orthopaedic limb surgeon

Nerves may be inadvertently injured during trauma surgery due to distorted anatomy, traction applied to a limb, soft tissue retraction, by power tools, instrumentation and from compartment syndrome. Elective orthopaedic surgery has additional risks of joint dislocation for arthroplasty surgery, limb lengthening, thermal injury from cement and direct injury from peripheral nerve blocks.The true incidence is unknown, and many cases are diagnosed as neurapraxia with the expectation of a full and timely recovery without the need for intervention. The incorrect assignation of a neurapraxia diagnosis may delay treatment for a higher grade of injury and in addition fails to recognize that a diagnosis of neurapraxia should be made with caution and a commitment to regular clinical review. Untreated, a neurapraxia can deteriorate and result in axonopathy. The failure to promptly diagnose such a nerve injury and instigate treatment may result in further deterioration and expose the clinician to medicolegal challenge.The focus of this review is to raise awareness of iatrogenic peripheral nerve injuries in orthopaedic limb surgery, the importance of regular clinical examination, the role of investigations, timing and nature of interventions and also to provide a guide to when onward referral to a specialist peripheral nerve injury unit is recommended. Cite this article: EFORT Open Rev 2021;6:607-617. DOI: 10.1302/2058-5241.6.200123.

Iatrogenic lesions of the peripheral nervous system in orthopaedic surgery and traumatology procedures

OBJECTIVE

To describe iatrogenic lesions of the peripheral nervous system and their relationship with different orthopaedic and traumatological procedures, through their assessment by means of electromyographic study.

MATERIAL AND METHODS

Retrospective descriptive study of the electromyographies performed in the clinical neurophysiology service of the Hospital General Universitari de Castelló between July 2015 and March 2019, recovering those in which the aetiology was diagnosed as iatrogenic in relation to surgical procedures and analysing those that were initiated after orthopaedic and traumatological procedures.

RESULTS

Of the total number of electromyographies reviewed, 1.37% corresponded to iatrogenic surgical lesions and 55.1% of these were secondary to orthopaedic surgery and traumatology procedures, the incidence in relation to the procedures performed was 0.65%. The most frequent locations related to injuries were the lumbar spine, hip and hand/wrist. Injuries due to postural causes not directly related to the surgical field are noteworthy.

CONCLUSION

Iatrogenic injuries to the peripheral nervous system after orthopaedic surgery and traumatology procedures are infrequent, but given their mechanism of injury and the high severity of most of them, it would be advisable to implement corrective mechanisms to reduce their incidence.

LEVEL OF EVIDENCE

IV.

The Prevention of Positioning Injuries During Gynecologic Surgery. Guideline of the DGGG, OEGGG and SGGG (S2k Level, AWMF Registry Number 015/077, October 2020)

Purpose Positioning injuries are relatively common, forensically highly relevant complications of gynecologic surgery. The aim of this official AWMF S2k-guideline is to provide statements and recommendations on how to prevent positioning injuries using the currently available literature. The literature was evaluated by an interdisciplinary group of experts from professional medical societies. The consensus on recommendations and statements was achieved in a structured consensus process. Method The current guideline is based on the expired S1-guideline, which was updated by a systematic search of the literature and a review of relevant publications issued between February 2014 and March 2019. Statements were compiled and voted on by a panel of experts. Recommendations The guideline provides general and specific recommendations on the prevention, diagnosis and treatment of positioning injuries.

Iatrogenic lesions of the peripheral nervous system in orthopaedic surgery and traumatology procedures

OBJECTIVE

To describe iatrogenic lesions of the peripheral nervous system and their relationship with different orthopaedic and traumatological procedures, through their assessment by means of electromyographic study.

MATERIAL AND METHODS

Retrospective descriptive study of the electromyographies performed in the clinical neurophysiology service of the Hospital General Universitari de Castelló between July 2015 and March 2019, recovering those in which the aetiology was diagnosed as iatrogenic in relation to surgical procedures and analysing those that were initiated after orthopaedic and traumatological procedures.

RESULTS

Of the total number of electromyographies reviewed, 1.37% corresponded to iatrogenic surgical lesions and 55.1% of these were secondary to orthopaedic surgery and traumatology procedures, the incidence in relation to the procedures performed was 0.65%. The most frequent locations related to injuries were the lumbar spine, hip and hand/wrist. Injuries due to postural causes not directly related to the surgical field are noteworthy.

CONCLUSION

Iatrogenic injuries to the peripheral nervous system after orthopaedic surgery and traumatology procedures are infrequent, but given their mechanism of injury and the high severity of most of them, it would be advisable to implement corrective mechanisms to reduce their incidence.

LEVEL OF EVIDENCE

IV.

Fluorescence labeling of a NaV1.7-targeted peptide for near-infrared nerve visualization

BACKGROUND

Accidental peripheral nerve injury during surgical intervention results in a broad spectrum of potentially debilitating side effects. Tissue distortion and poor visibility can significantly increase the risk of nerve injury with long-lasting consequences for the patient. We developed and characterized Hs1a-FL, a fluorescent near-infrared molecule for nerve visualization in the operating theater with the aim of helping physicians to visualize nerves during surgery. Hs1a was derived from the venom of the Chinese bird spider, Haplopelma schmidti, and conjugated to Cy7.5 dye. Hs1a-FL was injected intravenously in mice, and harvested nerves were imaged microscopically and with epifluorescence.

RESULTS

Hs1a-FL showed specific and stable binding to the sodium channel NaV1.7, present on the surface of human and mouse nerves. Hs1a-FL allowed epifluorescence visualization of sciatic mouse nerves with favorable nerve-to-muscle contrast.

CONCLUSIONS

Fluorescent NaV1.7-targeted tracers have the potential to be adopted clinically for the intraoperative visualization of peripheral nerves during surgery, providing guidance for the surgeon and potentially improving the standard of care.

Fascicular Ratio Pilot Study: High-Resolution Neurosonography-A Possible Tool for Quantitative Assessment of Traumatic Peripheral Nerve Lesions Before and After Nerve Surgery

BACKGROUND

Clinical and electrophysiological assessments prevail in evaluation of traumatic nerve lesions and their regeneration following nerve surgery in humans. Recently, high-resolution neurosonography (HRNS) and magnetic resonance neurography have gained significant importance in peripheral nerve imaging. The use of the grey-scale-based "fascicular ratio" (FR) was established using both modalities allowing for quantitative assessment.

OBJECTIVE

To find out whether FR using HRNS can assess nerve trauma and structural reorganization in correlation to postoperative clinical development.

METHODS

Retrospectively, 16 patients with operated traumatic peripheral nerve lesions were included. The control group consisted of 6 healthy volunteers. All imaging was performed with a 15 to 6 MHz ultrasound probe (SonoSite X-Porte; Fujifilm, Tokyo, Japan). FR was calculated using Fiji () on 8-bit-images ("MaxEntropy" using "Auto-Threshold" plug-in).

RESULTS

Thirteen of 16 patients required autologous nerve grafting and 3 of 16 extra-intraneural neurolysis. There was no statistical difference between the FR of nonaffected patients' nerve portion with 43.48% and controls with FR 48.12%. The neuromatous nerve portion in grafted patients differed significantly with 85.05%. Postoperatively, FR values returned to normal with a mean of 39.33%. In the neurolyzed patients, FR in the affected portion was 78.54%. After neurolysis, FR returned to healthy values (50.79%). Ten of 16 patients showed clinical reinnervation.

CONCLUSION

To our best knowledge, this is the first description of FR using HRNS for quantitative assessment of nerve damage and postoperative structural reorganization. Our results show a significant difference in healthy vs lesioned nerves and a change in recovering nerve portions towards a more "physiological" ratio. Further evaluation in larger patient groups is required.

Use of fluoroscopic-guided transsacral block for the treatment of iatrogenic post-injection sciatic neuropathy: Report of three cases

Post-injection sciatic neuropathy (PISN) from an inadvertent intramuscular injection in the gluteal region is a type of iatrogenic sciatic nerve injury. Patients with neuropathic pain following PISN frequently experience disability leading to restrictions in daily activities and pain, which may be resistant to conventional treatments and physiotherapy in some cases. To date, minimal invasive procedures for neuropathic pain have been performed with various medications at the site of lesion. Herein, we report three adult male cases with PISN-associated neu- ropathic pain who were resistant to conservative management and were treated with fluoroscopy-guided transsacral block.

Shortwave infrared fluorescence in vivo imaging of nerves for minimizing the risk of intraoperative nerve injury

Here, we present a novel nerve specific imaging agent for preventing intraoperative nerve injuries based on SWIR QD-based in vivo imaging, which not only provides real-time and long-time SWIR images to intraoperatively identify nerves but can also markedly minimize the risk of iatrogenic nerve injuries during surgeries.

Fluorescence Imaging of Peripheral Nerves by a Nav1.7-Targeted Inhibitor Cystine Knot Peptide

Twenty million Americans suffer from peripheral nerve injury caused by trauma and medical disorders, resulting in a broad spectrum of potentially debilitating side effects. In one out of four cases, patients identify surgery as the root cause of their nerve injury. Particularly during tumor resections or after traumatic injuries, tissue distortion and poor visibility can challenge a surgeon's ability to precisely locate and preserve peripheral nerves. Intuitively, surgical outcomes would improve tremendously if nerves could be highlighted using an exogeneous contrast agent. In clinical practice, however, the current standard of care-visual examination and palpation-remains unchanged. To address this unmet clinical need, we explored the expression of voltage-gated sodium channel Na_v1.7 as an intraoperative marker for the peripheral nervous system. We show that expression of Na_v1.7 is high in peripheral nerves harvested from both human and mouse tissue. We further show that modification of a Na_v1.7-selective peptide, Hsp1a, can serve as a targeted vector for delivering a fluorescent sensor to the peripheral nervous system. Ex vivo, we observe a high signal-to-noise ratio for fluorescently labeled Hsp1a in both histologically prepared and fresh tissue. Using a surgical fluorescent microscope, we show in a simulated clinical scenario that the identification of mouse sciatic nerves is possible, suggesting that fluorescently labeled Hsp1a tracers could be used to discriminate nerves from their surrounding tissues in a routine clinical setting.

Management of Iatrogenic Nerve Injuries

Iatrogenic peripheral nerve injuries from orthopaedic surgery can occur via many scenarios, including direct injury to the nerve during surgery, indirect injury via retraction or compartment syndrome, and injury from nonsurgical treatments such as injections and splinting. Successful management of iatrogenic nerve injuries requires an accurate diagnosis and timely, appropriate treatment. All orthopaedic surgeons must understand the preclinical study of nerve injury and the evaluation and treatment options for iatrogenic nerve injuries. Although a sharply transected nerve can be repaired immediately in the operating room under direct visualization, many injuries are not appreciated until the postoperative period. Advances in diagnostic studies and nerve repair techniques, nerve grafting, and nerve transfers have improved our ability to identify and treat such injuries.

A Neglected Cause of Iatrogenic Brachial Plexus Injuries in Psychiatric Patients

BACKGROUND

Psychiatric patients are often kept immobilized during hospitalization to avoid self-inflicted injuries and danger to third parties. Inadequate positioning can lead to brachial plexus injuries (BPI).

OBJECTIVE

To present a series of 5 psychiatric patients with BPI after being left sedated and restrained for prolonged periods of time during hospitalization.

METHODS

We retrospectively reviewed the charts of 5 psychiatric patients with iatrogenic BPI referred by other institutions to our service. The restraint technique adopted by those institutions consisted of a high-thoracic restraint. All patients underwent complete clinical and neurological examination at our center. Information concerning patient demographics, BPI characteristics, treatment choice, and ultimate outcome was recorded.

RESULTS

Three patients were male. The age of our patients ranged from 25 to 61 years old (mean: 41.2; median: 43). Three patients had a diagnosis of bipolar disorder while 2 had schizophrenia. Duration of immobilization ranged from 5 to 168 h (mean: 77.8; median: 72). Four patients presented with a unilateral right-sided lesion. Time to presentation ranged from 1 to 9 mo (mean: 4.2; median: 4). All patients also had intense pain and axillary lesions. Four patients received conservative treatment with partial or full functional recovery and complete pain resolution. The remaining patients underwent surgical repair and experienced good functional outcome.

CONCLUSION

Psychiatric patients who need to be sedated and immobilized must be monitored closely, as BPI can occur from high-thoracic restraints. When such an injury occurs, the patient must be referred to a center specialized in peripheral nerve surgery and rehabilitation.

Real-Time Fluorescence Imaging in Thoracic Surgery

Near-infrared (NIR) fluorescence imaging provides a safe and cost-efficient method for immediate data acquisition and visualization of tissues, with technical advantages including minimal autofluorescence, reduced photon absorption, and low scattering in tissue. In this review, we introduce recent advances in NIR fluorescence imaging systems for thoracic surgery that improve the identification of vital tissues and facilitate the resection of tumorous tissues. When coupled with appropriate NIR fluorophores, NIR fluorescence imaging may transform current intraoperative thoracic surgery methods by enhancing the precision of surgical procedures and augmenting postoperative outcomes through improvements in diagnostic accuracy and reductions in the remission rate.

Polyethylene Glycol: The Future of Posttraumatic Nerve Repair? Systemic Review

Peripheral nerve injury is a common posttraumatic complication. The precise surgical repair of nerve lesion does not always guarantee satisfactory motor and sensory function recovery. Therefore, enhancement of the regeneration process is a subject of many research strategies. It is believed that polyethylene glycol (PEG) mediates axolemmal fusion, thus enabling the direct restoration of axon continuity. It also inhibits Wallerian degeneration and recovers nerve conduction. This systemic review, performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, describes and summarizes published studies on PEG treatment efficiency in various nerve injury types and repair techniques. Sixteen original experimental studies in animal models and one in humans were analyzed. PEG treatment superiority was reported in almost all experiments (based on favorable electrophysiological, histological, or behavioral results). To date, only one study attempted to transfer the procedure into the clinical phase. However, some technical aspects, e.g., the maximal delay between trauma and successful treatment, await determination. PEG therapy is a promising prospect that may improve the surgical treatment of peripheral nerve injuries in the clinical practice.

The distance of the femoral neurovascular bundle from the hip joint: an intraoperative guide to reduce iatrogenic injury

Background

Iatrogenic injury to the femoral neurovascular bundle is not uncommon during primary and revision total hip replacement (THR) and can result in permanent weakness, pain and poor function. Prevention of injury to these structures relies on a sound knowledge of their relationships to the hip joint.

Methods

We studied 115 consecutive hip magnetic resonance imaging (MRI) results in order to identify objective relationships between these structures and the hip joint that can be used intraoperatively.

Results

We determined that the shortest mean distances of the femoral nerve, artery and vein from the hip joint are 23.62 (standard deviation, SD = 5.44), 19.62 (SD = 4.17) and 17.47 (SD = 4.41) mm, respectively. The femoral nerve was lateral to the hip joint in 30 (55.5%) left- and 37 (60.7%) right-sided hip joints. The femoral artery was located medial to the hip joint in 28 (51.9%) left- and 34 (55.7%) right-sided hips. The femoral vein was medial to the hip joint in 52 (96.3%) left- and 58 (95.1%) right-sided hips.

Conclusion

We have identified objective relationships between the hip joint and femoral neurovascular bundle that can be used with ease intraoperatively during THR. Our data show that patients with a low body weight and the elderly may be at a higher risk of iatrogenic injury due to increased proximity of the neurovascular structures to the hip. Application of this knowledge may serve to reduce the risk of iatrogenic injury to these structures and thereby improve patient satisfaction and outcomes.

Real-time, label-free, intraoperative visualization of peripheral nerves and micro-vasculatures using multimodal optical imaging techniques

Accurate, real-time identification and display of critical anatomic structures, such as the nerve and vasculature structures, are critical for reducing complications and improving surgical outcomes. Human vision is frequently limited in clearly distinguishing and contrasting these structures. We present a novel imaging system, which enables noninvasive visualization of critical anatomic structures during surgical dissection. Peripheral nerves are visualized by a snapshot polarimetry that calculates the anisotropic optical properties. Vascular structures, both venous and arterial, are identified and monitored in real-time using a near-infrared laser-speckle-contrast imaging. We evaluate the system by performing in vivo animal studies with qualitative comparison by contrast-agent-aided fluorescence imaging.

Surgical Management of Distal Biceps Tendon Anatomical Reinsertion Complications: Iatrogenic Posterior Interosseous Nerve Palsy

Background

Although iatrogenic posterior interosseous nerve (PIN) palsy is an uncommon complication of ruptured distal biceps brachii tendon surgical anatomical reinsertion, it is the most severe complication leading to functional limitation. The present study investigated possible types of PIN palsy as a postoperative complication of anatomical distal biceps tendon reinsertion, and aimed to clinically assess patients at 2 years after its surgical treatment.

Material/Methods

The studied sample comprised 7 male patients diagnosed with an iatrogenic PIN palsies after anatomical reinsertion of the distal biceps tendon, who were referred to the reference center for management of a peripheral nervous system injury. The nerve injury was intraoperatively evaluated. The clinical assessment used the Medical Research Council (MRC) System for motor recovery, and the Quick Disability of the Arm, Shoulder, and Hand (Quick DASH) was performed before the surgical treatment of the PIN injuries and at 2 years postoperatively. In all studied cases, electromyography was performed preoperatively and postoperatively.

Results

The comparison of the preoperative (x=1.43±0.53) and postoperative (x=4.71±0.49) results of the motor recovery of the PIN demonstrated a statistically significant improvement (p<0.001). Moreover, the results of functional assessments with the use of the Quick DASH questionnaire significantly improved (p<0.001) postoperatively (x=6.14±6.86) compared to the preoperative evaluations (x=54.29±12.05).

Conclusions

The PIN palsies as complications of the surgical anatomical reinsertion of ruptured distal biceps brachii resulted from mechanical nerve compression or direct intraoperative damage. The 2-year outcomes justified the clinical use of surgical management for iatrogenic PIN palsy.

Common peripheral nerve injuries in sport: diagnosis and management

Peripheral nerve injuries are unusual in sport but impact an athlete's safe return to play. Nerve injuries result from either acute trauma (most commonly in contact/collision sports) or from repetitive microtrauma and overuse. Diagnosis of overuse nerve injuries includes nerve localization and surrounding soft-tissue anatomy, and must account for possible causes of repetitive microtrauma, including biomechanics, equipment, training schedule, and recovery. Prognosis is related to the type of nerve injury. Management should not simply be rest and gradual return to sport but should address biomechanical and training predispositions to injury. Understanding the type of injury and the tissues involved will guide appropriate rehabilitation decisions. Recognizing acute care considerations and implementing appropriate strategies can help minimize secondary trauma to an area following acute injury.

Mechanisms, Treatment, and Patient Outcome of Iatrogenic Injury to the Brachial Plexus-A Retrospective Single-Center Study

BACKGROUND

Injury to the brachial plexus is a devastating condition, with severe impairment of upper extremity function resulting in distinct disability. There are no systematic reports on epidemiology, causative mechanisms, treatment strategies. or outcomes of iatrogenic brachial plexus injury (iBPI).

METHODS

We screened all cases of iatrogenic nerve injuries recorded between 2007 and 2017 at a single specialized institution. Mechanism of iBPI, type of previous causative intervention, location and type of the lesion as well as the type of revision surgery and functional patient outcome were analyzed.

RESULTS

We identified 14 cases of iBPI, which all presented with significant impairment of upper extremity motor function (at least 1 muscle Medical Research Council grade 0). Neuropathic pain was present in most patients (11/14). Orthopedic shoulder procedures such as rotator cuff fixation, arthroplasty, and repositioning of a clavicle fracture accounted for iBPI in 7 of 14 patients. Other reasons for iBPI were resection or biopsy of a peripheral nerve sheath tumor in 3 patients or lymph node situated at the cervicomediastinal area in 2 patients. Mechanisms also included transaxillary rib resection in one and sternotomy in another patient. The treatment of iBPI was conducted according to each individual's needs and included neurolysis in 4, nerve grafting in 9, and nerve transfers in 1 patient. We found improved symptoms after treatment in most patients (11/14).

CONCLUSIONS

Most common causes for iBPI were shoulder surgery and resection or biopsy of peripheral nerve sheath tumor and lymph nodes. Early referral to specialized peripheral nerve centers may help to improve functional patient outcome.

4.7-T diffusion tensor imaging of acute traumatic peripheral nerve injury

Diagnosis and management of peripheral nerve injury is complicated by the inability to assess microstructural features of injured nerve fibers via clinical examination and electrophysiology. Diffusion tensor imaging (DTI) has been shown to accurately detect nerve injury and regeneration in crush models of peripheral nerve injury, but no prior studies have been conducted on nerve transection, a surgical emergency that can lead to permanent weakness or paralysis. Acute sciatic nerve injuries were performed microsurgically to produce multiple grades of nerve transection in rats that were harvested 1 hour after surgery. High-resolution diffusion tensor images from ex vivo sciatic nerves were obtained using diffusion-weighted spin-echo acquisitions at 4.7 T. Fractional anisotropy was significantly reduced at the injury sites of transected rats compared with sham rats. Additionally, minor eigenvalues and radial diffusivity were profoundly elevated at all injury sites and were negatively correlated to the degree of injury. Diffusion tensor tractography showed discontinuities at all injury sites and significantly reduced continuous tract counts. These findings demonstrate that high-resolution DTI is a promising tool for acute diagnosis and grading of traumatic peripheral nerve injuries.

Iatrogenic lesions of peripheral nerves

Iatrogenic nerve lesions (INLs) are an integral part of peripheral neurology and require dedicated neurologists to manage them. INLs of peripheral nerves are most frequently caused by surgery, immobilization, injections, radiation, or drugs. Early recognition and diagnosis is important not to delay appropriate therapeutic measures and to improve the outcome. Treatment can be causative or symptomatic, conservative, or surgical. Rehabilitative measures play a key role in the conservative treatment, but the point at which an INL requires surgical intervention should not be missed or delayed. This is why INLs require close multiprofessional monitoring and continuous re-evaluation of the therapeutic effect. With increasing number of surgical interventions and increasing number of drugs applied, it is quite likely that the prevalence of INLs will further increase. To provide an optimal management, more studies about the frequency of the various INLs and studies evaluating therapies need to be conducted. Management of INLs can be particularly improved if those confronted with INLs get state-of-the-art education and advanced training about INLs. Management and outcome of INLs can be further improved if the multiprofessional interplay is optimized and adapted to the needs of the patient, the healthcare system, and those responsible for sustaining medical infrastructure.

The Prevention of Positioning Injuries during Gynecologic Operations. Guideline of DGGG (S1-Level, AWMF Registry No. 015/077, February 2015)

Purpose: Official guideline published and coordinated by the German Society of Gynecology and Obstetrics (DGGG). Positioning injuries after lengthy gynecological procedures are rare, but the associated complications can be potentially serious for patients. Moreover, such injuries often lead to claims of malpractice and negligence requiring detailed medical investigation. To date, there are no binding evidence-based recommendations for the prevention of such injuries. Methods: This S1-guideline is the work of an interdisciplinary group of experts from a range of different professions who were commissioned by DGGG to carry out a systematic literature search of positioning injuries. Members of the participating scientific societies develop a consensus in an informal procedure. Afterwards the directorate of the scientific society approves the consensus. The recommendations cover.

Improved Intraoperative Visualization of Nerves through a Myelin-Binding Fluorophore and Dual-Mode Laparoscopic Imaging

The ability to visualize and spare nerves during surgery is critical for avoiding chronic morbidity, pain, and loss of function. Visualization of such critical anatomic structures is even more challenging during minimal access procedures because the small incisions limit visibility. In this study, we focus on improving imaging of nerves through the use of a new small molecule fluorophore, GE3126, used in conjunction with our dual-mode (color and fluorescence) laparoscopic imaging instrument. GE3126 has higher aqueous solubility, improved pharmacokinetics, and reduced non-specific adipose tissue fluorescence compared to previous myelin-binding fluorophores. Dosing and kinetics were initially optimized in mice. A non-clinical modified Irwin study in rats, performed to assess the potential of GE3126 to induce nervous system injuries, showed the absence of major adverse reactions. Real-time intraoperative imaging was performed in a porcine model. Compared to white light imaging, nerve visibility was enhanced under fluorescence guidance, especially for small diameter nerves obscured by fascia, blood vessels, or adipose tissue. In the porcine model, nerve visualization was observed rapidly, within 5 to 10 minutes post-intravenous injection and the nerve fluorescence signal was maintained for up to 80 minutes. The use of GE3126, coupled with practical implementation of an imaging instrument may be an important step forward in preventing nerve damage in the operating room.

Intraoperative peripheral nerve injury in colorectal surgery. An update

Intraoperative peripheral nerve injury during colorectal surgery procedures is a potentially serious complication that is often underestimated. The Trendelenburg position, use of inappropriately padded armboards and excessive shoulder abduction may encourage the development of brachial plexopathy during laparoscopic procedures. In open colorectal surgery, nerve injuries are less common. It usually involves the femoral plexus associated with lithotomy position and self-retaining retractor systems. Although in most cases the recovery is mostly complete, treatment consists of physical therapy to prevent muscular atrophy, protection of hypoesthesic skin areas and analgesics for neuropathic pain. The aim of the present study is to review the incidence, prevention and management of intraoperative peripheral nerve injury.

Iatrogenic nerve injuries: prevalence, diagnosis and treatment

BACKGROUND

Iatrogenic nerve injuries can result from direct surgical trauma, mechanical stress on a nerve due to faulty positioning during anesthesia, the injection of neurotoxic substances into a nerve, and other mechanisms. Treating physicians should know the risk factors and the procedure to be followed when an iatrogenic nerve injury arises.

METHOD

This review is based on pertinent articles retrieved by a selective search in PubMed and on the authors' own data from the years 1990-2012.

RESULTS

In large-scale studies, 25% of sciatic nerve lesions that required treatment were iatrogenic, as were 60% of femoral nerve lesions and 94% of accessory nerve lesions. Osteosyntheses, osteotomies, arthrodeses, lymph node biopsies in the posterior triangle of the neck, carpal tunnel operations, and procedures on the wrist and knee were common settings for iatrogenic nerve injury. 340 patients underwent surgery for iatrogenic nerve injuries over a 23-year period in the District Hospital of Günzburg (Neurosurgical Department of the University of Ulm). In a study published by the authors in 2001, 17.4% of the traumatic nerve lesions treated were iatrogenic. 94% of iatrogenic nerve injuries occurred during surgical procedures.

CONCLUSION

A thorough knowledge of the anatomy of the vulnerable nerves and of variants in their course can lessen the risk of iatrogenic nerve injury. When such injuries arise, early diagnosis and planning of further management are the main determinants of outcome. If adequate nerve regeneration does not occur, surgical revision should optimally be performed 3 to 4 months after the injury, and 6 months afterward at the latest. On the other hand, if postoperative high resolution ultrasound reveals either complete transection of the nerve or a neuroma in continuity, surgery should be performed without any further delay. If the surgeon becomes aware of a nerve transection during the initial procedure, then either immediate end-to-end suturing or early secondary management after three weeks is indicated.

Pectoralis major transfer for the management of scapula winging secondary to serratus anterior injury or paralysis

Pectoralis major transfer (partial or complete) is the most common transfer to the scapula for winging as a result of serratus anterior paralysis or injury. The most commonly described technique is to transfer the pectoralis major prolonged with tendon allograft or autograft to the scapula. We present a technique that entails direct transfer of the sternal head of the pectoralis major with its bony insertion to the lower scapula.

[Peripheral nerve lesions of the lower leg due to tibiofibular ganglion]

Cystic formations around the knee are a common object of orthopedic treatment. When associated with neurological or vascular deficits further diagnostic imaging is required. This case study demonstrates the appearance of an intramuscular ganglion causing drop foot, arising from the tibio-fibular joint.

Preventing perioperative peripheral nerve injuries

Peripheral nerve injuries are largely preventable injuries that can result from incorrect patient positioning during surgery. Patients who are diabetic, are extremely thin or obese, use tobacco, or undergo surgery lasting more than four hours are at increased risk for developing these injuries. When peripheral nerve injuries occur, patients may experience numbness, burning, or tingling and may have difficulty getting out of bed, walking, gripping objects, or raising their arms. These symptoms can interrupt activities of daily living and impede recovery. Signs and symptoms of peripheral nerve injury may appear within 24 to 48 hours of surgery or may take as long as a week to appear. Careful attention to body alignment and proper padding of bony prominences when positioning patients for surgery is necessary to prevent peripheral nerve injury. The use of a preoperative assessment tool to identify at-risk patients, collaboration between physical therapy and OR staff members regarding patient positioning, and neurophysiological monitoring can help prevent peripheral nerve injuries.

Intraoperative fluorescence imaging of peripheral and central nerves through a myelin-selective contrast agent

Purpose

Patients suffer from complications as a result of unintentional nerve damage during surgery. We focus on improving intraoperative visualization of nerves through the use of a targeted fluorophore and optical imaging instrumentation.

Procedure

A myelin-targeting fluorophore, GE3111, was synthesized, characterized for its optical and myelin-binding properties using purified myelin basic protein, and evaluated in mice. Additionally, a compact instrument was adapted to visualize nerves.

Results

GE3111 was synthesized using a versatile methodology. Its optical properties were sensitive to the local environment both in vitro and in vivo. Following intravenous injection, central and peripheral nerves were visualized, with the kinetics of nerve uptake modifiable depending on the formulation. Fluorescence polarization showed specific and strong binding to purified myelin basic protein. Nerves were visualized in vivo using a dedicated compact imaging device requiring less than 2.5 mW/cm² of illumination at 405 nm.

Conclusions

Fluorescence imaging of nerves through myelin showed a potential for use in image-guided surgery. Intraoperative nerve imaging is an example where contrast agent and instrument development come together as a result of clinical need.

Electronic supplementary material

The online version of this article (doi:10.1007/s11307-012-0555-1) contains supplementary material, which is available to authorized users.

Identification of the protein target of myelin-binding ligands by immunohistochemistry and biochemical analyses

The ability to visualize myelin is important in the diagnosis of demyelinating disorders and the detection of myelin-containing nerves during surgery. The development of myelin-selective imaging agents requires that a defined target for these agents be identified and that a robust assay against the target be developed to allow for assessment of structure-activity relationships. We describe an immunohistochemical analysis and a fluorescence polarization binding assay using purified myelin basic protein (MBP) that provides quantitative evidence that MBP is the molecular binding partner of previously described myelin-selective fluorescent dyes such as BMB, GE3082, and GE3111.

Repair of a median nerve transection injury using multiple nerve transfers, with long-term functional recovery

Complete loss of median nerve motor function is a rare but devastating injury. Loss of median motor hand function and upper-extremity pronation can significantly impact a patient's ability to perform many activities of daily living independently. The authors report the long-term follow-up in a case of median nerve motor fiber transection that occurred during an arthroscopic elbow procedure, which was then treated with multiple nerve transfers. Motor reconstruction used the nerves to the supinator and extensor carpi radialis brevis to transfer to the anterior interosseous nerve and pronator. Sensory sensation was restored using the lateral antebrachial cutaneous (LABC) nerve to transfer to a portion of the sensory component of the median nerve, and a second cable of LABC nerve as a direct median nerve sensory graft. The patient ultimately recovered near normal motor function of the median nerve, but had persistent pain symptoms 4 years postinjury.

Scapular winging: an update

Scapular winging is a rare disorder often caused by neuromuscular imbalance in the scapulothoracic stabilizer muscles. Lesions of the long thoracic nerve and spinal accessory nerves are the most common cause. Numerous underlying etiologies have been described. Patients report diffuse neck, shoulder girdle, and upper back pain, which may be debilitating, associated with abduction and overhead activities. Accurate diagnosis and detection depend on appreciation of the scapulothoracic anatomy and a comprehensive physical examination. Although most cases resolve nonsurgically, surgical treatment of scapular winging has been met with success.