A brief history of surgery for peripheral nerve sheath tumors

Preventive Effect of Local Lidocaine Administration on the Formation of Traumatic Neuroma

BACKGROUND

Traumatic neuroma is a common sequela of peripheral nerve injury or amputation, which often leads to severe neuropathic pain. The present study investigated the effect of local lidocaine administration on preventing the formation of traumatic neuroma.

METHODS

Forty-eight male Sprague-Dawley rats were randomly assigned to two groups. The lidocaine group underwent sciatic nerve transection, followed by an injection of lidocaine (0.5%) around the proximal of a severed sciatic nerve under ultrasound-guidance 2-7 days after neurectomy. In the control group, rats received an injection of saline following neurectomy. The autotomy score, mechanical allodynia, thermal hyperalgesia, histological assessment, expression of neuroma, and pain-related markers were detected.

RESULTS

Lidocaine treatment reduced the autotomy score and attenuated mechanical allodynia and thermal hyperalgesia. The mRNA expression of α-SMA, NGF, TNF-α, and IL-1β all significantly decreased in the lidocaine group in comparison to those in the saline control group. The histological results showed nerve fibers, demyelination, and collagen hyperplasia in the proximal nerve stump in the saline control group, which were significantly inhibited in the lidocaine group.

CONCLUSIONS

The present study demonstrated that local lidocaine administration could inhibit the formation of painful neuroma due to traumatic nerve injury.

Surgical Approaches for Prevention of Neuroma at Time of Peripheral Nerve Injury

Painful neuroma is a frequent sequela of peripheral nerve injury which can result in pain and decreased quality of life for the patient, often necessitating surgical intervention. End neuromas are benign neural tumors that commonly form after nerve transection, when axons from the proximal nerve stump regenerate in a disorganized manner in an attempt to recreate nerve continuity. Inflammation and collagen remodeling leads to a bulbous end neuroma which can become symptomatic and result in decreased quality of life. This review covers surgical prophylaxis of end neuroma formation at time of injury, rather than treatment of existing neuroma and prevention of recurrence. The current accepted methods to prevent end neuroma formation at time of injury include different mechanisms to inhibit the regenerative response or provide a conduit for organized regrowth, with mixed results. Approaches include proximal nerve stump capping, nerve implantation into bone, muscle and vein, various pharmacologic methods to inhibit axonal growth, and mechanisms to guide axonal growth after injury. This article reviews historical treatments that aimed to prevent end neuroma formation as well as current and experimental treatments, and seeks to provide a concise, comprehensive resource for current and future therapies aimed at preventing neuroma formation.

Clinical results after surgical resection of benign solitary schwannomas: A review of 150 cases

INTRODUCTION

Peripheral nerve schwannomas are the most common nerve tumors. While they are efficiently treated with surgery, the risk of neurological complications, especially sensory deficits, remains debated.

HYPOTHESIS

We postulate that rates of post-operative sensory deficits in peripheral schwannoma surgery are low and are not increased in schwannomas of the hand, in which preservation of discriminative tact is of prime functional importance.

MATERIALS AND METHODS

A retrospective multicenter study was carried out on 150 patients with an isolated peripheral schwannoma operated between 2002 and 2018, including 11 patients with schwannomas of the hand. All cases were reviewed preoperatively and postoperatively with a detailed exam of the neurological status.

RESULTS

Most schwannomas were located in the lower limbs (58%). The two main affected trunks were the posterior tibial nerve in the lower limb and the median nerve in the upper limb. The average preoperative tumor volume measured on MRI was 2.93 cm³ [0.11 cm³-25 cm³]. The most common preoperative symptoms were paresthesia (77.1%) and pseudo-Tinel sign (55.7%). Less frequently, pain (50.3%) and hypoesthesia (18.1%) were observed. On the other hand, preoperative neurological motor manifestations remained exceptional (3.3%). The rates of new post-operative motor deficits, paresthesias, and sensory deficits were 4.6%, 10.9% and 8% respectively and were not increased in schwannomas of the collateral nerves of the hand.

CONCLUSION

Surgical resection is a safe procedure for peripheral nerve schwannoma treatment with satisfying functional results and an acceptable risk of nerve injury, especially for sensory function.

LEVEL OF PROOF

D; Multicenter retrospective study.

A Photosealed Cap Prevents Disorganized Axonal Regeneration and Neuroma following Nerve Transection in Rats

Neuroma is a common sequela of traumatic peripheral nerve injury that can result in pain and decreased quality of life for patients. Neuromas result from axonal outgrowth in an attempt to reestablish continuity with the disrupted distal nerve end. Photosealing is a light-activated technique whereby tissues can be securely isolated in a strong and secure manner. This study investigated whether photosealing of autologous vein and crosslinked human amniotic membrane (xHAM) to cap the proximal stump of transected sciatic nerve would prevent disorganized axonal regeneration and neuroma in a rat model.

Morphological Relation of Peripheral Nerve Sheath Tumors and Nerve Fascicles: Prospective Study and Classification

Removal of benign peripheral nerve sheath tumors (bPNST) represents a surgical challenge. The morphological relation of bPNST and healthy nerve fascicles are of utmost importance for achieving both removal of the entire tumor and preservation of functional integrity of the peripheral nerve. Thus, we intraoperatively assessed the morphological patterns between bPNST and nerve fascicles using photo documentation obtained between January 2009 and September 2021. In 31 patients (20 women and 11 men) with a mean age of 48 ± 18 years a total of 34 bPNST were removed. Four constant morphological patterns between bPNST relatively to nerve fascicles were detected: (1) bPNST is located peripherally (n = 16), (2) it splits the nerve into two main fascicles (n = 5), (3) it totally splits up the nerve out of the nerve's center (n = 8) und (4) it encloses the nerve and its fascicles (n = 5) without any detectable boundary layer. Histology revealed 28 schwannomas, five neurofibromas, and one perineurioma. The proposed classification reflects the increasing complexity of tumor removal with a higher type number. This might be beneficial for preoperative diagnostics, i.e., high-resolution ultrasound or MRI-tractography, as well as for planning the bPNST's surgical resection and the possible need for nerve reconstruction.

The clinical course and role of surgery in pediatric malignant peripheral nerve sheath tumors: a database study

OBJECTIVE

Malignant peripheral nerve sheath tumors (MPNSTs) are rare tumors found throughout the body, with their clinical course in children still not completely understood. Correspondingly, this study aimed to determine survival outcomes and specific clinical predictors of survival in this population from a large national database.

METHODS

All patients with MPNSTs aged ≤ 18 years in the US National Cancer Database (NCDB) between 2005 and 2016 were retrospectively reviewed. Data were summarized, and overall survival was modeled using Kaplan-Meier and Cox regression analyses.

RESULTS

A total of 251 pediatric patients with MPNSTs (132 [53%] females and 119 [47%] males) were identified; the mean age at diagnosis was 13.1 years (range 1-18 years). There were 84 (33%) MPNSTs located in the extremities, 127 (51%) were smaller than 1 cm, and 22 (9%) had metastasis at the time of diagnosis. In terms of treatment, surgery was pursued in 187 patients (74%), chemotherapy in 116 patients (46%), and radiation therapy in 129 patients (61%). The 5-year overall survival rate was estimated at 52% (95% CI 45%-59%), with a median survival of 64 months (range 36-136 months). Multivariate regression revealed that older age (HR 1.10, p < 0.01), metastases at the time of diagnosis (HR 2.14, p = 0.01), and undergoing biopsy only (HR 2.98, p < 0.01) significantly and independently predicted a shorter overall survival. Chemotherapy and radiation therapy were not statistically significant.

CONCLUSIONS

In this study, the authors found that older patient age, tumor metastases at the time of diagnosis, and undergoing only biopsy significantly and independently predicted poorer outcomes. Only approximately half of patients survived to 5 years. These results have shown a clear survival benefit in pursuing maximal safe resection in pediatric patients with MPNSTs. As such, judicious workup with meticulous resection by an expert team should be considered the standard of care for these tumors in children.

Recurrent Schwannomatosis of the Hand

Background: Peripheral nerve sheath tumors (PNSTs) are neoplastic soft tissue masses generated from the abnormal proliferation of Schwann cells. Often, these tumors occur in isolation and are known as schwannomas or neurilemmomas. The presence of multiple schwannomas is known as schwannomatosis. The purpose of this article is 2-fold: (1) to review the relevant literature and describe a unique case of this rare condition; and (2) to emphasize salient clinical considerations in the diagnosis and treatment of schwannomatosis. Methods: In this report, we describe the case of a 52-year-old white man who presented with multiple recurrent soft tissue masses of the right hand. On initial presentation, he described pain across his right hand and index finger, which persisted despite numerous prior operations. The index finger had a flexion contracture around the location of the proximal interphalangeal joint, and there were multiple tender masses along the length of the finger and palm. Results: Segmental excision of the affected radial digital nerve was performed. A pulp flap based on contralateral neurovascular bundle resulted in a sensate, pain-free digit. Tissue pathology confirmed the diagnosis of multiple neurilemmomas. Conclusions: We report the success of a radial digital neurectomy in a patient with widespread neurilemmomas, who had previously excluded that painful digit from use. It was through careful consideration of the preoperative differential diagnosis, by valuing the preoperative imaging, and by considering all surgical options with specific attention paid to skin flap design that this good outcome of a fully sensate, pain-free, mobile index finger was achieved.

Go for the Gold: A “Plane” and Simple Technique for Resecting Benign Peripheral Nerve Sheath Tumors

BACKGROUND

Intraneural dissection is a useful technique for achieving gross total resection and preserving functional fascicles for peripheral nerve tumors. Finding the correct tissue plane is the critical step for safe successful enucleation. The authors hypothesized that the yellow color of benign nerve tumors can be used to identify surgical planes.

OBJECTIVE

To describe a technique to find the correct intraneural dissection plane based on a quantified yellow appearance during resection of benign peripheral nerve sheath tumors.

METHODS

Intraoperative photographs were reviewed to determine the percentage of yellow that tumors appeared at different phases of surgery. A technique was developed to quantitatively measure the amount of yellow using Photoshop. Previously published journal articles containing color images of peripheral nerve tumor resections were also analyzed for yellow tumor color.

RESULTS

There were 24 patients with suitable images to permit measurement of color for 3 steps of the procedure. The average percentages of yellow for tumor exposure, tumor resection, and removed specimen were 36.5%, 59.1%, and 80.4%, respectively (P &lt; .001). Three publications were found that contained high-quality images of at least 2 phases of the surgery with average yellow content of 47.4% and 84% (P &lt; .01).

CONCLUSION

The simple observation that a benign nerve sheath tumor is yellow in color can be used to guide surgical resection and achieve excellent outcomes. Intraneural dissection through the pseudocapsule should be pursued layer by layer until a yellow true capsule is found. By sparing functional nervous tissue within the pseudocapsule, this technique may lead to improved neurological outcomes.

Painful Terminal Neuroma Prevention by Capping PRGD/PDLLA Conduit in Rat Sciatic Nerves

Neuroma formation after amputation as a long-term deficiency leads to spontaneous neuropathic pain that reduces quality of life of patients. To prevent neuroma formation, capping techniques are implemented as effective treatments. However, an ideal, biocompatible material covering the nerves is an unmet clinical need. In this study, biocompatible characteristics presented by the poly(D,L-lactic acid)/arginylglycylaspartic acid (RGD peptide) modification of poly{(lactic acid)-co- [(glycolic acid)-alt-(L-lysine)]} (PRGD/PDLLA) are evaluated as a nerve conduit. After being capped on the rat sciatic nerve stump in vivo, rodent behaviors and tissue structures are compared via autotomy scoring and histological analyses. The PRGD/PDLLA capped group gains lower autotomy score and improves the recovery, where inflammatory infiltrations and excessive collagen deposition are defeated. Transmission electron microscopy images of the regeneration of myelin sheath in both groups show that abnormal myelination is only present in the uncapped rats. Changes in related genes (MPZ, MBP, MAG, and Krox20) are monitored quantitative real-time polymerase chain reaction (qRT-PCR) for mechanism investigation. The PRGD/PDLLA capping conduits not only act as physical barriers to inhibit the invasion of inflammatory infiltration in the scar tissue but also provide a suitable microenvironment for promoting nerve repairing and avoiding neuroma formation during nerve recovery.