Intraoperative recording of the bulbocavernosus reflex

Intraoperative Monitoring of the External Urethral Sphincter Reflex: A Novel Adjunct to Bulbocavernosus Reflex Neuromonitoring for Protecting the Sacral Neural Pathways Responsible for Urination, Defecation and Sexual Function

PURPOSE

Intraoperative bulbocavernosus reflex neuromonitoring has been utilized to protect bowel, bladder, and sexual function, providing a continuous functional assessment of the somatic sacral nervous system during surgeries where it is at risk. Bulbocavernosus reflex data may also provide additional functional insight, including an evaluation for spinal shock, distinguishing upper versus lower motor neuron injury (conus vs. cauda syndromes) and prognosis for postoperative bowel and bladder function. Continuous intraoperative bulbocavernosus reflex monitoring has been utilized to provide the surgeon with an ongoing functional assessment of the anatomical elements involved in the S2-S4 mediated reflex arc including the conus, cauda equina and pudendal nerves. Intraoperative bulbocavernosus reflex monitoring typically includes the electrical activation of the dorsal nerves of the genitals to initiate the afferent component of the reflex, followed by recording the resulting muscle response using needle electromyography recordings from the external anal sphincter.

METHODS

Herein we describe a complementary and novel technique that includes recording electromyography responses from the external urethral sphincter to monitor the external urethral sphincter reflex. Specialized foley catheters embedded with recording electrodes have recently become commercially available that provide the ability to perform intraoperative external urethral sphincter muscle recordings.

RESULTS

We describe technical details and the potential utility of incorporating external urethral sphincter reflex recordings into existing sacral neuromonitoring paradigms to provide redundant yet complementary data streams.

CONCLUSIONS

We present two illustrative neurosurgical oncology cases to demonstrate the utility of the external urethral sphincter reflex technique in the setting of the necessary surgical sacrifice of sacral nerve roots.

The diagnostic accuracy of neuromonitoring for detecting postoperative bowel and bladder dysfunction in spinal oncology surgery: a case series

PURPOSE

Postoperative bowel and bladder dysfunction (BBD) poses a significant risk following surgery of the sacral spinal segments and sacral nerve roots, particularly in neuro-oncology cases. The need for more reliable neuromonitoring techniques to enhance the safety of spine surgery is evident.

METHODS

We conducted a case series comprising 60 procedures involving 56 patients, spanning from September 2022 to January 2024. We assessed the diagnostic accuracy of sacral reflexes (bulbocavernosus and external urethral sphincter reflexes) and compared them with transcranial motor evoked potentials (TCMEP) incorporating anal sphincter (AS) and external urethral sphincter (EUS) recordings, as well as spontaneous electromyography (s-EMG) with AS and EUS recordings.

RESULTS

Sacral reflexes demonstrated a specificity of 100% in predicting postoperative BBD, with a sensitivity of 73.33%. While sensitivity slightly decreased to 64.71% at the 1-month follow-up, it remained consistently high overall. TCMEP with AS/EUS recordings did not identify any instances of postoperative BBD, whereas s-EMG with AS/EUS recordings showed a sensitivity of 14.29% and a specificity of 97.14%.

CONCLUSION

Sacral reflex monitoring emerges as a robust adjunct to routine neuromonitoring, offering surgeons valuable predictive insights to potentially mitigate the occurrence of postoperative BBD.

The predictive value of intraoperative bulbocavernosus reflex monitoring for postoperative voiding function in patients with conus medullaris and cauda equina tumors: a retrospective single center study

BACKGROUND CONTEXT

Surgical resection is the preferred treatment in most conus medullaris and cauda equina tumor (CMCET) cases. However, total resection is usually challenging to obtain and has a strong possibility of causing various complications if forcibly attempted. Intraoperative neurophysiological monitoring (IONM) has become a necessary adjunctive tool for CMCET resection.

PURPOSE

The current study aimed to evaluate the application value of bulbocavernosus reflex (BCR) monitoring in CMCET surgery.

STUDY DESIGN

A retrospective clinical study.

PATIENT SAMPLE

The medical records of patients who underwent CMCET resection by the same neurosurgical team at our hospital from September 2020 to June 2022 were retrospectively reviewed. IONM was conducted in all surgeries. According to inclusion criteria and exclusion criteria, ultimately, 105 patients were enrolled in the study.

OUTCOME MEASURES

The voiding function was assessed before surgery, 1 month after, and 6 months after surgery using the Neurogenic Bladder Symptom Score (NBSS). If the NBSS obtained 1 month after surgery exceeds 9 points than that before surgery, it can be considered that the patient suffered new-onset postoperative voiding dysfunctions (PVDs). Moreover, if the NBSS could restored (less than 9 points higher than before the surgery) at 6 months after surgery, it was defined as a short-term PVD. Otherwise, it was defined as a long-term PVD.

METHODS

The amplitude reduction ratios (ARRs) of bilateral BCR waveforms were calculated and compared between patients with PVDs and those without. The receiver operating characteristic curve analysis was subsequently applied to determine the cut-off value of the maximal and minimal ARRs for predicting PVDs.

RESULTS

The maximal and minimal ARRs were significantly correlated with short-term and long-term PVDs (p<.001 for all comparisons, Mann-Whitney U test). The threshold values of maximal ARR for predicting short-term and long-term PVD were 68.80% (AUC=0.996, p<.001) and 72.10% (AUC=0.996, p<.001), respectively. While those of minimal ARR were 50.20% (AUC=0.976, p<.001) and 53.70% AUC=0.999, p<.001).

CONCLUSIONS

The amplitude reduction of intraoperative bilateral BCR waveforms showed high predictive value for PVDs.

Intraoperative somatosensory evoked potential (SEP) monitoring: an updated position statement by the American Society of Neurophysiological Monitoring

Somatosensory evoked potentials (SEPs) are used to assess the functional status of somatosensory pathways during surgical procedures and can help protect patients' neurological integrity intraoperatively. This is a position statement on intraoperative SEP monitoring from the American Society of Neurophysiological Monitoring (ASNM) and updates prior ASNM position statements on SEPs from the years 2005 and 2010. This position statement is endorsed by ASNM and serves as an educational service to the neurophysiological community on the recommended use of SEPs as a neurophysiological monitoring tool. It presents the rationale for SEP utilization and its clinical applications. It also covers the relevant anatomy, technical methodology for setup and signal acquisition, signal interpretation, anesthesia and physiological considerations, and documentation and credentialing requirements to optimize SEP monitoring to aid in protecting the nervous system during surgery.

Conception and implementation of an MRI-compatible device to elicit the bulbocavernosus reflex for an open spinal cord study

OBJECTIVE

Functional MRI (fMRI) can be employed to assess neuronal activity in the central nervous system. However, investigating the spinal cord using fMRI poses several technical difficulties. Enhancing the fMRI signal intensity in the spinal cord can improve the visualization and analysis of different neural pathways, particularly those involved in bladder function. The bulbocavernosus reflex (BCR) is an excellent method for evaluating the integrity of the sacral spinal cord. Instead of stimulating the glans penis or clitoris, the BCR can be simulated comfortably by tapping the suprapubic region. In this study, we explain the necessity and development of a device to elicit the simulated BCR (sBCR) via suprapubic tapping while conducting an fMRI scan.

METHODS

The device was successfully tested on a group of 20 healthy individuals. Two stimulation task block protocols were administered (empty vs. full bladder). Each block consisted of 40 s of suprapubic tapping followed by 40 s of rest, and the entire sequence was repeated four times.

RESULTS

Our device can reliably and consistently elicit sBCR noninvasively as demonstrated by electromyographic recording of pelvic muscles and anal winking. Participants did note mild to moderate discomfort and urge to void during the full bladder task.

CONCLUSION

Our device demonstrates an efficacious approach to elicit sBCR within an MRI bore to assess sacral spinal cord functional activity without generating any significant motion artifacts.

SIGNIFICANCE

This device can explore the mechanisms and processes controlling urinary, digestive, or sexual function within this region in humans.

Identifying Suspected Volume Conduction Contamination of External Anal Sphincter Motor Evoked Potentials in Lumbosacral Spine Surgery

PURPOSE

Iatrogenic injury to sacral nerve roots poses significant quality of life issues for patients. Motor evoked potential (MEP) monitoring can be used for intraoperative surveillance of these important structures. We hypothesized that volume conducted depolarizations from gluteus maximus (GM) may contaminate external anal sphincter (EAS) MEP results during lumbosacral spine surgery.

METHODS

Motor evoked potential from the EAS and medial GM in 40 patients were prospectively assessed for inter-muscle volume conduction during lumbosacral spine surgeries. Peak latency matching between the EAS and GM MEP recordings conditionally identified volume conduction (VC+) or no volume conduction (VC-). Linear regression and power spectral density analysis of EAS and medial GM MEP amplitudes were performed from VC+ and VC- data pairs to confirm intermuscle electrical cross-talk.

RESULTS

Motor evoked potential peak latency matching identified putative VC+ in 9 of 40 patients (22.5%). Mean regression coefficients (r2) from peak-to-peak EAS and medial GM MEP amplitude plots were 0.83 ± 0.04 for VC+ and 0.34 ± 0.06 for VC- MEP (P < 0.001). Power spectral density analysis identified the major frequency component in the MEP responses. The mean frequency difference between VC+ EAS and medial GM MEP responses were 0.4 ± 0.2 Hz compared with 3.5 ± 0.6 Hz for VC- MEP (P < 0.001).

CONCLUSIONS

Our data support using peak latency matching between EAS and GM MEP to identify spurious MEP results because of intermuscle volume conduction. Neuromonitorists should be aware of this possible cross-muscle conflict to avoid interpretation errors during lumbosacral procedures using EAS MEP.

Updates on Intraoperative Neurophysiology During Surgery for Spinal Dysraphism

Spinal dysraphism is a group of disorders resulting from an embryologic failure of spinal cord development which can lead to a radicular-medullary mechanical stretch that generates vascular compromise and hypoxic-ischemic damage to the nervous structures of the conus-cauda region.Thus, the clinical relevance of the different types of spinal dysraphism is related to the possible neurologic deficits resulting from spinal cord tethering. The clinical presentation is heterogenous: from asymptomatic to very compromised patients. The indications and the time of a detethering surgery are still subject of debate, although there is an agreement on the high standards of treatment that have to be offered by the surgery. Intraoperative neurophysiology (ION) contributes to the safety of tethered cord surgery in reducing the risks of iatrogenic neurological damages.

Intraoperative bulbocavernosus reflex monitoring in posterior lumbar fusion surgery

OBJECTIVE

To assess the utility of intraoperative bulbocavernosus reflex (BCR) monitoring in posterior lumbar fusion surgery.

METHODS

We retrospectively evaluated 153 patients undergoing posterior lumbar fusion with intraoperative BCR monitoring. Voiding function was assessed at discharge and two follow-ups.

RESULTS

BCR was preserved in 151 patients and completely disappeared in two patients at the end of surgery. For patients in whom BCR was preserved, voiding difficulties at discharge and 1-month and 6-month follow-ups were noted in 16 (10.6%), 9 (6.0%), and 0 (0.0%) patients, respectively. However, patients with BCR loss experienced voiding difficulties at all three time-points. Statistical analysis showed a significant difference in voiding between those with preserved and disappeared BCRs at 6 months postoperatively. BCR disappeared during surgery but recovered before the end of surgery in six patients. Among these patients, one experienced transient voiding difficulties postoperatively but with good recovery. However, the other five patients did not experience postoperative voiding difficulties.

CONCLUSIONS

BCR had low sensitivity for voiding dysfunction at discharge, but had high accuracy at 6-month follow-up examinations. BCR loss was associated with new voiding dysfunction.

SIGNIFICANCE

Intraoperative BCR monitoring is a potentially useful tool for enhancing safety during posterior lumbar fusion by predicting postoperative voiding dysfunction.

Intraoperative neuromonitoring during surgery for lumbar stenosis

The indications for neuromonitoring during lumbar stenosis surgery are defined by the risks associated with patient positioning, the approach, decompression of neural elements, deformity correction, and instrument implantation. The routine use of EMG and SEP alone during lumbar stenosis surgery is no longer supported by the literature. Lateral approach neuromonitoring with EMG only is also suspect. Lumbar stenosis patients often present with multiple co-morbidities which put them at risk during routine pre-surgical positioning. Frequently encountered morbid obesity and/or diabetes mellitus may play a role in monitorable and preventable brachial plexopathy after "superman" positioning or femoral neuropathy from groin pressure after prone positioning, for example. Deformity correction in lumbar stenosis surgery often demands advanced implementation of multiple neuromonitoring modalities: EMG, SEP, and MEP. Because the bulbocavernosus reflex detects the function of the conus medullaris and sacral somato afferent/efferent fibers of the cauda equina, it may also be recorded. The recommendation to record pedicle screw thresholds has become more nuanced as surgeon dependence on 3D imaging, navigation, and robotics has increased. Neuromonitoring in lumbar stenosis surgery has been subject mainly to uncontrolled case series; prospective cohort trials are also needed.

Monitoring spinal surgery for extramedullary tumors and fractures

Meningiomas are the most common intradural extramedullary tumors, followed by nerve sheath tumors that can also grow extradurally. Metastases are the most frequent extradural tumors and most commonly affect the thoracic vertebrae. Spinal fractures with column dislocation and/or instability require surgical fixation. Spine surgery for an extramedullary tumor or fracture usually involves decompression of neural elements and instrumentation for stabilization. These procedures risk spinal cord and nerve root injury. The incidence of nerve root deficits after resection of nerve sheath tumors is particularly high since the tumor grows from the rootlets. Intraoperative neurophysiologic monitoring and mapping techniques have been introduced to prevent iatrogenic neurologic deficits. These include motor and sensory evoked potentials, electromyography, compound muscle action potentials, and the bulbocavernosus reflex. The combination of techniques chosen for a particular procedure depends on the surgical level and the character of the lesion.

Mapping and monitoring of tethered cord and cauda equina surgeries

Surgery involving the cauda equina and tethered cord can be associated with significant functional disability including pain, motor and sensory deficits, as well as bladder, bowel, and sexual dysfunction. Neurophysiologic intraoperative monitoring and mapping during these surgeries using a variety of techniques and applications contributes to lessen the risk of permanent injury. This chapter reviews the anatomy of the pelvic floor, describes the techniques involved in monitoring and mapping this area, and describes the limitations of neurophysiology applications. Additionally, this chapter details mapping and monitoring techniques as they apply to tethered cord surgical release in both children and adults with review of outcome studies, and describes complications which can arise from tethered cord repair and injury to the cauda equina despite appropriate neurophysiologic intraoperative involvement.

Relationship between Preoperative Neuroradiological Findings and Intraoperative Bulbocavernosus Reflex Amplitude in Patients with Intradural Extramedullary Tumors

The current study aimed to evaluate the relationship between preoperative neuroradiological findings and intraoperative bulbocavernosus reflex (BCR) amplitude in patients with intradural extramedullary tumors. A total of 24 patients with lesions below the 12th thoracic vertebra were included in the analysis. Objective and subjective urinary symptoms were investigated using data obtained from medical records and the core lower urethral symptom score (CLSS) questionnaire. The lesion compression rate was evaluated with MRI. In the epiconus-to-conus medullaris (Epi-CM) group, BCR amplitude changes were found to be correlated with the compression rate (p <0.05). The preoperative CLSS of the group with a BCR amplitude of <50% was worse than that of the group with ≥50% (p <0.01). The group did not experience symptom improvement 6 months postoperatively based on the CLSS. The preoperative CLSS of the group with compression rate of ≥80% on imaging was worse than that of the group with <80% (p <0.05). In the group with preoperative compression rate of ≥80%, CLSS at 1 month and 6 months postoperatively was improved as compared to preoperative CLSS (p <0.01, p <0.05). Hence, BCR amplitude changes are associated with the degree of lesion compression on preoperative images and pre- and postoperative urinary symptoms. Patients with intradural extramedullary Epi-CM lesions with strong compression are likely to present with low BCR amplitude and worsened postoperative symptoms. It is considered that the risk of postoperative urinary symptoms increases even with careful surgical manipulation under these conditions.

Efficacy of intraoperative bulbocavernosus reflex monitoring for the prediction of postoperative voiding function in adult patients with lumbosacral spinal tumor

Lumbosacral spinal tumor surgery is associated with a relatively high risk of postoperative voiding dysfunction. This study aimed to investigate the correlation between intraoperative bulbocavernosus reflex (BCR) changes and postoperative voiding function in adult patients with lumbosacral spinal tumors. We retrospectively reviewed 63 patients who underwent intradural conus and cauda equina tumor surgeries with intraoperative BCR monitoring. We evaluated patients' voiding functions for 6 months postoperatively. BCR was maintained in 60 patients and disappeared in 3 patients at the end of the surgery. Among the patients in whom BCR was maintained, examinations conducted at discharge and at 1- and 6-month follow-ups revealed that 7 (11.7%), 4 (6.7%), and zero (0.0%) patients experienced voiding difficulty, respectively. However, all 3 (100%) patients without BCR experienced voiding difficulty at the three corresponding follow-ups. Data analysis indicated no significant difference in voiding between the maintained and disappeared BCR groups 6-months postoperatively. The sensitivity, specificity, positive predictive, and negative predictive values of intraoperative BCR monitoring for detecting new and worsening difficulty in voiding were all 100% 6 months postoperatively. Our results shows that intraoperative BCR monitoring is a reliable predictor of voiding function following surgery in adult patients undergoing lumbosacral spinal tumor surgery. Intraoperative BCR monitoring can be useful for assessing and monitoring the integrity of the voiding function during lumbosacral spinal tumor surgery.

Early de-tethering: analysis of urological and clinical consequences in a series of 40 children

PURPOSE

Early de-tethering procedures are performed on spinal dysraphisms to prevent neuro-urological deterioration caused by growth. Partial lipoma removal may cause delayed deterioration by re-tethering, while complete removal may increase the risk of postoperative worsening. The present study evaluates the risk of postoperative deterioration and the protective potential of intraoperative neurophysiological monitoring (IOM), with a special reference to the conus lipomas treated with the radical approach.

METHODS

Forty toddlers (< 24 months) underwent complete perioperative neurological and urological assessment, including urodynamic study (UDS). The dysraphisms were subgrouped according to Pang's classification. IOM was applied in all patients: transcranial motor evoked potentials (tMep) combined with mapping were recorded in all cases while bulbocavernosus reflex (BCR) was evaluable just in 7 cases.

RESULTS

At preoperative evaluation, 11 children already had UDS impairment and 2 had motor disturbances before neurosurgery. At 1-month follow-up, preoperative motor disturbances were stable, 7/11 UDS alterations normalized, and the remaining 4 were stable. At 6-month follow-up, all motor deficits and 8/11 preoperative UDS alterations had improved. Unfortunately, 7 children with previously normal UDS experienced a new impairment after surgery: 2/7 normalized while 5/7 did not recover. This postoperative permanent urodynamic impairment occurred in 4 chaotic lipoma (CLchaos) and in one terminal myelocystocele (TMC) that means a surgical deterioration rate of 22% for the high risk cases.

CONCLUSIONS

This small highly selected series confirms that early de-tethering may stop or revert the spontaneous neuro-urological deterioration: in fact, preoperative UDS impairment was frequent (27.5%) and improved in all the low surgical risk cases (limited dorsal myeloschisis, filar, transitional and dorsal lipomas). On the contrary, in CLchaos and TMC, early de-tethering was unable to revert preoperative UDS impairment, and radical surgery carried a high risk of new neuro-urological deterioration directly caused by the operation. In our experience, IOM had a protective role for motor functions, while it was less effective for the neuro-urological ones, probably due to the anesthesiology regimens applied. In conclusion, among the dysraphisms, CLchoas proved to be the worst enemy that often camouflages at MRI. Affording it without all possible IOM weapons carries a high risk to harm the patient.

Bulbocavernosus Reflex Monitoring During Intramedullary Conus Tumor Surgery

A T10 to L2 spinal cord tumor exploration and biopsy was performed with intraoperative neurophysiological monitoring (IONM) on a 75-year-old male diagnosed with an intradural intramedullary appearing spinal cord lesion with no other lesions in the central nervous system, chest, abdomen or pelvis.

Intraoperative neurophysiology consisted of transcranial electrical motor evoked potentials (TCeMEPs), somatosensory evoked potentials (SSEPs), triggered and spontaneous electromyography (S-EMG, T-EMG), bulbocavernosus reflex (BCR) and train of four (TOF) monitoring. Loss of BCR responses during conus exposure and identification were resolved with multiple small pauses in manipulation throughout the procedure. T-EMG mapping aided in identification and avoiding the removal of nervous tissue.

Postoperatively the patient experienced some mild weakness in his left foot and leg that correlated with a significant amplitude drop in the left abductor hallucis TCeMEP. By the following day, the patient was almost back to preoperative baseline. The patient’s bowel and bladder function were preserved, consistent with final BCR recordings. The patient was discharged to rehabilitation postoperatively. Pathology results indicated glioblastoma.

This case study demonstrates the utility of a multimodality approach with bulbocavernosus reflex and urethral sphincter monitoring to optimize intraoperative data to the surgeon during conus tumor surgeries.

Intraoperative neurophysiological monitoring of the bulbocavernosus reflex during surgery for conus spinal lipoma: what are the warning criteria?

OBJECTIVE

Despite the surge in the intraoperative use of the bulbocavernosus reflex (BCR) during lumbosacral surgeries, there are as yet no widely accepted BCR warning criteria for use with intraoperative neurophysiological monitoring (IONM). The author's aim was to find clinically acceptable warning criteria for use in IONM of the BCR.

METHODS

Records of IONM of the BCR in 164 operations in 163 patients (median age 5 months) with a conus spinal lipoma who underwent surgery between August 2002 and May 2016 were retrospectively analyzed. The outcomes of IONM of the BCR were grouped by the residual amplitude at the end of surgery: group 1, ≥ 50%; group 2, 25%-50% (including the lower bound, but not the upper); and group 3, < 25%. Cases in which the BCR was lost were separately assessed as a subgroup of group 3. The postoperative urinary complication rate was used to verify the warning criteria zones.

RESULTS

The BCR could be monitored in 149 surgeries (90.9%). There were 118 surgeries (79.2%) in group 1, 18 (12.1%) in group 2, and 13 (8.7%) in group 3. Two surgeries (11.1%) in group 2 and 6 (46.2%) in group 3 resulted in urinary complications. In the group 3 subgroup (lost BCR), all 5 surgeries resulted in urinary complications. The cutoff value of the BCR amplitude reduction was placed between groups 1 and 2 (zone 1: cutoff 50%), groups 2 and 3 (zone 2: cutoff 25%), and group 3 and its subgroup (zone 3: cutoff zero, present or lost). In zone 1, the positive predictive value (PPV) was 25.8% and the negative predictive value (NPV) was 100%. In zone 2, the PPV was 53.8% and the NPV 98.5%. In zone 3, the PPV was 100% and the NPV 97.9%. The PPV was highest in zone 3. The NPV was highest in zone 1, but its PPV was low (25.8%).

CONCLUSIONS

The "lost or remained" criterion of BCR amplitude (zone 3: cutoff zero) can be used as a predictor of postoperative urinary function. As a warning criterion, the cutoff value of the BCR amplitude reduction at 75% (zone 2) may be used. This preliminary clinical report on the warning criteria for the BCR may contribute to improving the safety of surgery for conus spinal lipoma.

Intraoperative feasibility of bulbocavernosus reflex monitoring during untethering surgery in infants and children

Bulbocavernosus reflex (BCR) monitoring is used to assess the integrity of urinary and bowel function. In this study, we evaluated the feasibility of BCR monitoring during untethering surgery in infants and children to predict postoperative urinary and bowel dysfunction. The records of 22 patients ranging from 4 days to 10 years old (mean 2.7 ± 3.3 years) were reviewed. Anesthesia was maintained by propofol or sevoflurane/opioid without neuromuscular blockade. BCR waveforms induced by electrical stimulation (20-40 mA, train-of-four pulses with 500 Hz) to the penis or clitoris were recorded from bilateral external anal sphincters. To assess the sensitivity and specificity of BCR monitoring, we investigated the association between a significant continuous decrease in BCR amplitude at the end of surgery and postoperative urinary and bowel dysfunction after surgery. Reproducible baseline BCR waveforms were successfully recorded in 20 of 22 patients (90.9%). A significant continuous decrease in BCR amplitude was observed in 8 patients. The results of intraoperative BCR monitoring included three true-positives, twelve true-negatives, five false-positives, and zero false-negatives. Therefore, the sensitivity and specificity of BCR monitoring used to predict postoperative urinary and bowel dysfunction were 100 and 70.6%, respectively. BCR monitoring during untethering surgery in infants and children under general anesthesia was found to be a feasible method to prevent postoperative urinary and bowel dysfunction.

The Bulbocavernosus Reflex in the Differential Diagnosis of Multiple System Atrophy with Predominant Parkinsonism and Parkinson's Disease

Multiple system atrophy with predominant parkinsonism (MSA-P) is a degenerative disorder that presents with autonomic dysfunction, atypical parkinsonism, and ataxia. Parkinson's disease (PD) is an age-related neurological disorder of the central nervous system. Differentiation between MSA-P and PD is important because treatments, complications, and prognoses differ. The bulbocavernosus reflex (BCR) tests the afferent and efferent signals of the pudendal nerve as well as the sacral cord. In this study, we investigated differences in BCR parameters between MSA-P and PD patients. Thirty-eight MSA-P patients and 32 PD patients were selected to participate in our electrophysiological investigations. The Keypoint EMG/EP system was used to induce the BCR, and latencies and amplitudes were recorded for systematic statistical analyses. Area under the curve of the receiver operating characteristic was used to assess the specificity and sensitivity of the BCR parameters. A BCR was elicited in 76.32% of MSA-P patients and 93.75% of PD patients. The BCR latencies of the MSA-P group were longer than those of the PD group (p < 0.001). In addition, the MSA-P group had a lower BCR amplitude compared to the PD and control groups (p < 0.001). We discovered the difference between MSA-P and PD through BCR latencies and amplitudes. Compared to PD patients, MSA-P patients have longer latencies and lower amplitudes. Therefore, the BCR may be used to discriminate between MSA-P and PD in some cases.

Intraoperative neurophysiological mapping and monitoring in spinal tumor surgery: sirens or indispensable tools?

Spinal tumor (ST) surgery carries the risk of new neurological deficits in the postoperative period. Intraoperative neurophysiological monitoring and mapping (IONM) represents an effective method of identifying and monitoring in real time the functional integrity of both the spinal cord (SC) and the nerve roots (NRs). Despite consensus favoring the use of IONM in ST surgery, in this era of evidence-based medicine, there is still a need to demonstrate the effective role of IONM in ST surgery in achieving an oncological cure, optimizing patient safety, and considering medicolegal aspects. Thus, neurosurgeons are asked to establish which techniques are considered indispensable. In the present study, the authors focused on the rationale for and the accuracy (sensitivity, specificity, and positive and negative predictive values) of IONM in ST surgery in light of more recent evidence in the literature, with specific emphasis on the role of IONM in reducing the incidence of postoperative neurological deficits. This review confirms the role of IONM as a useful tool in the workup for ST surgery. Individual monitoring and mapping techniques are clearly not sufficient to account for the complex function of the SC and NRs. Conversely, multimodal IONM is highly sensitive and specific for anticipating neurological injury during ST surgery and represents an important tool for preserving neuronal structures and achieving an optimal postoperative functional outcome.