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.

Value of electrophysiological indicators in differential diagnosis of parkinson's disease and multiple system atrophy.

BACKGROUND: We evaluated the value of electrophysiological indicators by external anal sphincter electromyography (EAS-EMG), sympathetic skin response (SSR), R-R interval variation (RRIV), and Bulbocavernosus Reflex (BCR) in differential diagnosis of multiple system atrophy (MSA) and Parkinson's disease (PD). METHODS: A total of 41 patients with MSA and 32 patients with PD were enrolled. The electrophysiological changes of autonomic dysfunction were assessed with BCR, EAS-EMG, SSR, and RRIV, and the abnormal rate of each indicator was calculated. The diagnostic value of each indicator was analyzed with ROC curve. RESULTS: The incidence rate of autonomic dysfunction in MSA group was significantly higher than that in PD group (p < 0.05). The abnormal rates of BCR and EAS-EMG indicators in MSA group were higher than those in PD group (p < 0.05). The abnormal rates of SSR and RRIV indicators in MSA group and PD group were high; however, there was no significant difference between MSA and PD groups (p > 0.05). The sensitivity of BCR combined with EAS-EMG indicators in differential diagnosis of MSA and PD were 92.3% in males and 86.7% in females, respectively, and the specificity was 72.7% in males and 90% in females, respectively. CONCLUSIONS: Combined analysis of BCR and EAS-EMG has high sensitivity and specificity for differential diagnosis of MSA and PD.

Comparison of intraoperative neurophysiological monitoring methods for lumbosacral lipoma surgery in infants.

BACKGROUND: Stable intraoperative neurophysiology monitoring of infants, especially very young infants, is challenging. In this study, motor evoked potentials (MEPs), the bulbocavernosus reflex (BCR), and somatosensory evoked potentials (SEPs) were simultaneously monitored in infants with lumbosacral lipomas, and these methods were compared retrospectively. METHODS: A total of 21 surgeries performed for lumbosacral lipoma in patients less than 1 year old were studied. The mean age at surgery was 133.8 days (range 21-287 days; ≤ 120 days: 9 cases, > 120 days: 12 cases). Transcranial MEPs were measured in the anal sphincter and gastrocnemius, and tibialis anterior and other muscles were added as needed. The BCR was measured by the electromyogram of the anal sphincter muscle with stimulation of the pubic region, and SEPs were measured from the waveforms of stimulation of the posterior tibial nerves. RESULTS: For the BCR, stable potentials could be recorded for all 9 cases at ≤ 120 days of age. In contrast, for MEPs, stable potentials could be recorded in only 4 of 9 cases (p < 0.05). For all patients > 120 days of age, MEPs and the BCR were measurable. SEPs were undetectable in some patients regardless of age. CONCLUSION: The BCR could be more consistently measured than MEPs in infant patients with lumbosacral lipoma at ≤ 120 days of age.

Surgery for spina bifida occulta: spinal lipoma and tethered spinal cord.

The technical evolution of the surgery for spina bifida occulta (SBO) over the course of a half-century was reviewed with special foci placed on the spinal lipoma and tethered spinal cord. Looking back through history, SBO had been included in spina bifida (SB). Since the first surgery for spinal lipoma in the mid-nineteenth century, SBO has come to be recognized as an independent pathology in the early twentieth century. A half-century ago, the only option available for SB diagnosis was the plain X-ray, and pioneers of the time persevered in the field of surgery. The classification of spinal lipoma was first described in the early 1970s, and the concept of tethered spinal cord (TSC) was proposed in 1976. Surgical management of spinal lipoma with partial resection was the most widely practiced approach and was indicated only for symptomatic patients. After understanding TSC and tethered cord syndrome (TCS), more aggressive approaches became preferred. A PubMed search suggested that there was a dramatic increase of publications on the topic beginning around 1980. There have been immense academic achievements and technical evolutions since then. From the authors' viewpoint, landmark achievements in this field are listed as follows: (1) establishment of the concept of TSC and the understanding of TCS; (2) unraveling the process of secondary and junctional neurulation; (3) introduction of modern intraoperative neurophysiological mapping and monitoring (IONM) for surgery of spinal lipomas, especially the introduction of bulbocavernosus reflex (BCR) monitoring; (4) introduction of radical resection as a surgical technique; and (5) proposal of a new classification system of spinal lipomas based on embryonic stage. Understanding the embryonic background seems critical because different embryonic stages bring different clinical features and of course different spinal lipomas. Surgical indications and selection of surgical technique should be judged based on the background embryonic stage of the spinal lipoma. As time flows forward, technology continues to advance. Further accumulation of clinical experience and research will open the new horizon in the management of spinal lipomas and other SBO in the next half-century.

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.

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 value of the bulbocavernosus reflex and pudendal nerve somatosensory evoked potentials in distinguishing between multiple system atrophy and Parkinson's disease at an early stage.

OBJECTIVES: This study was designed to investigate the clinical value of the bulbocavernosus reflex (BCR) and pudendal nerve somatosensory evoked potentials (PSEPs) in the differential diagnosis between multiple system atrophy (MSA) and Parkinson's disease (PD) in early stage. MATERIALS AND METHODS: A total of 31 patients with MSA, 45 patients with PD, and 60 healthy participants were included in this study. A Keypoint EMG/EP system was used for BCR and PSEP measurements. Electrophysiological parameters were collected for statistical analysis. RESULTS: The BCR elicitation rates were significantly lower in the patients with MSA than in the patients with PD (P<.05). Prolonged BCR latencies were found in the MSA group compared to the PD and control groups (P<.05). Bulbocavernosus reflex latencies were significantly prolonged in patients with MSA compared with PD patients showing early urogenital symptoms (P<.05). There was no significant difference in PSEP P41 latencies among the three groups (P=.434 in males, P=.948 in females). Both BCR and PSEP amplitudes were significantly lower in the MSA/PD group than in the control group (P<.001). CONCLUSIONS: Pudendal nerve damage is more severe in MSA than in PD. Prolonged BCR latency may be valuable for distinguishing between MSA and PD in the early stages. BCR and PSEP testing may also contribute to localized and qualitative diagnosis of the distribution of neurodegenerative pathologies in these two disorders.

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.

Restoring penis sensation in patients with low spinal cord lesions: the role of the remaining function of the dorsal nerve in a unilateral or bilateral TOMAX procedure.

AIMS: The recently developed TOMAX-procedure restores unilateral genital sensation, improving sexual health in men with a low spinal lesion (LSL). It connects one dorsal nerve of the penis (DNP) to the intact ipsilateral ilioinguinal nerve. We proposed bilateral neurotization for full sensation of the glans but this entails cutting both DNPs, risking patients' erection/ejaculation ability. The objective was to select patients for a bilateral TOMAX-procedure by measuring remaining DNP function, and perform the first bilateral cases. METHODS: In 30 LSL patients with no penile- but normal groin sensation selected for a unilateral TOMAX-procedure the integrity of the sacral-reflex-arc and DNP function was tested pre-operatively using bilateral needle electromyography (EMG)-bulbocavernosus reflex (BCR) measurements, and an interview about reflex erections (RE) ability. RESULTS: In 13 spina bifida- and 17 spinal cord injury patients [median age 29.5 years (range 13-59 years), spinal lesion T12 (incomplete) to sacral], seven (23%) patients reported RE, four (57%) with intact BCR, and of nine (30%) patients with intact BCR, four reported RE (44%). CONCLUSIONS: Even patients with a LSL and no penile sensation can have signs of remaining DNP function, but cutting both DNPs to restore full glans sensation in a bilateral TOMAX-procedure might interfere with their RE/ejaculation. To avoid this risk, we propose a selecting-protocol for a unilateral- or bilateral procedure using RE and BCR measurements. Using this protocol, three patients were bilaterally operated with promising preliminary results. Full sensation of the glans could lead to further improvement in sexual function.

Bulbocavernosus Reflex Has No Prognostic Features During the Acute Evaluation of Spinal Cord Injuries.

The bulbocavernosus reflex (BCR) has been used during the initial evaluation of a spinal cord injury patient as a metric to determine prognosis and whether the patient is in "spinal shock." This reflex has been less utilized over the last decade, and therefore a review was performed to assess the value of BCR in patient prognosis. The North American Clinical Trials Network (NACTN) for Spinal Cord Injury (SCI) is a consortium of tertiary medical centers that includes a prospective SCI registry. The NACTN registry data was analyzed to evaluate the prognostic implication of the BCR during the initial evaluation of a spinal cord injury patient. SCI patients were divided into those with an intact or absent BCR during their initial evaluation. Associations of participants' descriptors and neurological status on follow-up were performed, followed by associations with the presence of a BCR. A total of 769 registry patients with recorded BCRs were included in the study. The median age was 49 years (32-61 years), and the majority were male (n = 566, 77%) and white (n = 519, 73%). Among included patients, high blood pressure was the most common comorbidity (n = 230, 31%). Cervical spinal cord injury was the most common (n = 470, 76%) with fall (n = 320, 43%) being the most frequent mechanism of injury. BCR was present in 311 patients (40.4%), while 458 (59.6%) had a negative BCR within 7 days of injury or before surgery. At 6 months post-injury, 230 patients (29.9%) followed up, of which 145 had a positive BCR, while 85 had a negative BCR. The presence/absence of BCR was significantly different in patients with cervical (p = 0.0015) or thoracic SCI (p = 0.0089), or conus medullaris syndrome (p = 0.0035), and in those who were American Spinal Injury Association Impairment Scale grade A (p = 0.0313). No significant relationship was observed between BCR results and demographics, AIS grade conversion, motor score changes (p = 0.1669), and changes in pin prick (p = 0.3795) and light touch scores (p = 0.8178). In addition, cohorts were not different in surgery decision (p = 0.7762) and injury to surgery time (p = 0.0681). In our review of the NACTN spinal cord registry, the BCR did not provide prognostic utility in the acute evaluation of spinal cord injury patients. Therefore, it should not be used as a reliable marker for predicting neurological outcomes post-injury.

Transurethral electrical stimulation for intraoperative bulbocavernosus reflex monitoring during spine surgery in females.

OBJECTIVE: Intraoperative bulbocavernosus reflex (BCR) monitoring is more difficult in females than in males. This study was designed to compare the feasibility of transurethral electrical stimulation BCR (tu-BCR) monitoring with that of conventional BCR (c-BCR) monitoring during spine surgery in females. METHODS: Twenty-four females were included. For stimulation in c-BCR monitoring, a pair of surface electrodes was placed on the genitals (cathode/anode: clitoris/adjacent labium). For stimulation in tu-BCR monitoring, a urethral catheter attached to a pair of electrodes was inserted into the urethra. BCRs were recorded from the external anal sphincter after a single train of four stimulation pulses. RESULTS: There was no postoperative urinary tract injury associated with urethral catheter insertion for tu-BCR. Tu-BCR monitoring had a significantly higher success rate of baseline recording than c-BCR monitoring (87.5% vs 66.7%, respectively, p = 0.028). The specificities of tu-BCR and c-BCR monitoring were 100% and 87.2%, respectively. The sensitivity was not calculated because no patients had postoperative urinary or bowel dysfunction. CONCLUSIONS: Our data indicate that tu-BCR monitoring improved the success rate of baseline recording and specificity during spine surgery in females. SIGNIFICANCE: Tu-BCR monitoring was more reliable than c-BCR monitoring during spine surgery in females.

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.

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.

Assessment of sacral spinal excitability using stimulus-response curves of the bulbocavernosus reflex.

OBJECTIVE: To analyze and quantify sacral spinal excitability through bulbocavernosus reflex (BCR) stimulus-response curves. METHODS: Thirty subjects with upper motor neuron lesions (UMN) and nine controls were included in this prospective, monocentric study. Sacral spinal excitability was assessed using stimulus-response curves of the BCR, modeled at different bladder filling volumes relative to the desire to void (as defined by the International Continence Society) during a cystometry. Variations in α (i.e. the slope of the stimulus-response curve) were considered as an indicator of the modulation of sacral spinal excitability. RESULTS: In all subjects, α increased during bladder filling suggesting the modulation of spinal sacral excitability during the filling phase. This increase was over 30% in 96.7% of neurological subjects and 88.9% of controls. The increase was higher before the first sensation to void in the neurological population (163.15%), compared to controls, (29.91%), p < 0.001. CONCLUSIONS: We showed the possibility of using BCR stimulus-response curves to characterize sacral spinal response with an amplification of this response during bladder filling as well as a difference in this response amplification in patients with UMN in comparison with a control group. SIGNIFICANCE: BCR, through stimulus-response curves, might be an indicator of pelvic-perineal exaggerated reflex response and possibly a tool for evaluating treatment effectiveness.

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?

OBJECTIVEDespite 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.METHODSRecords 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.RESULTSThe 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%).CONCLUSIONSThe "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.

Surgical management of complex spinal cord lipomas: how, why, and when to operate. A review.

This review summarizes the classification, anatomy, and embryogenesis of complex spinal cord lipomas, and it describes in some detail the new technique of total lipoma resection and radical reconstruction of the affected neural placode. Its specific mission is to tackle two main issues surrounding the management of complex dysraphic lipomas: whether total resection confers better long-term benefits than partial resection and whether total resection fares better than conservative treatment-i.e., no surgery-for asymptomatic lipomas. Accordingly, the 24-year progression-free survival data of the author and colleagues' series of over 300 cases of total resection are compared with historical data from multiple series (including the author and colleagues' own) of partial resection, and total resection data specifically for asymptomatic lesions are compared with the two known series of nonsurgical treatment of equivalent numbers of patients. These comparisons amply support the author's recommendation of total resection for most complex lipomas, with or without symptoms. The notable exception is the asymptomatic chaotic lipoma, whose peculiar anatomical relationship with the neural tissue defies even this aggressive surgical approach and consequently projects worse results (admittedly of a small number of cases) than for the other two lipoma subtypes of dorsal and transitional lesions. Prophylactic resection of asymptomatic chaotic lipomas is therefore not currently endorsed.

Predictive value of intraoperative bulbocavernosus reflex during untethering surgery for post-operative voiding function.

OBJECTIVE: To evaluate the clinical significance of intraoperative bulbocavernosus reflex (BCR) during untethering surgery in predicting post-operative voiding function. METHODS: We conducted a retrospective review of pediatric patients who underwent untethering surgery with available intraoperative baseline BCR. BCR response during surgery was classified into loss or maintenance. Post-operative voiding function was determined as worsened or maintained based on history, postvoid residual urine measurement, and urodynamic study (UDS). Data regarding demographics, diagnosis, pre-operative voiding difficulty, re-untethering, syrinx, and abnormalities in electromyography were collected for analysis. RESULTS: We included 106 patients, with a mean age of 3.3 years, and 49 patients were male. BCR was lost in 15 patients during surgery and voiding function worsened in 14 patients after surgery. Lumbosacral lipoma was the most common diagnosis, and 16 patients were diagnosed with lipomyelomeningocele (LMMC). The sensitivity and specificity of intraoperative BCR for post-operative worsening of voiding function were 35.7%, and 88.5% at 6 months, respectively. The diagnosis of LMMC was statistically significant in a logistic regression analysis. The specificity of BCR at 6 months in patients with diagnosis other than LMMC was 93.4%, and intraoperative BCR was significant in a logistic regression analysis. CONCLUSIONS: Intraoperative BCR during untethering could predict bladder function 6 months post-operatively with high specificity (88.5%), particularly in cases other than LMMC (93.4%), indicating that voiding function deterioration will not occur if intraoperative BCR is preserved. SIGNIFICANCE: Intraoperative BCR during untethering surgery is a useful tool to predict post-operative voiding outcome.

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.

Optimal stimulation parameters for intraoperative bulbocavernosus reflex in infants.

OBJECTIVE The aim of this study was to establish optimal electric stimulation parameters for intraoperatively monitoring the bulbocavernosus reflexes (BCRs) in infants. METHODS The authors retrospectively reviewed the medical records of all infants (age < 24 months) who had undergone an untethering operation for tethered cord syndrome between May 2013 and February 2014 at a single institution and whose baseline BCR had been elicited during surgery. Using different combinations of stimulation parameters-number of stimulation pulses: 4 or 8 pulses, interpulse interval: 1, 2, or 5 msec, and polarity of stimulation: biphasic or monophasic-the authors compared the relative mean amplitude of 10 BCR responses (rmaBCRs) to each combination of parameters. RESULTS The rmaBCRs were larger with the 8-pulse stimulations than with the 4-pulse stimulations (p < 0.0001). There was a tendency, though not statistically significant, for larger rmaBCRs to be obtained with the longer interpulse interval in the 8-pulse stimulation (p = 0.1289). The biphasic stimulation produced larger rmaBCRs than the monophasic stimulation (p = 0.0005). CONCLUSIONS Biphasic 8-pulse stimulations with 5-msec or 2-msec intervals yield the largest BCR responses. Considering that an 8-pulse stimulation with 5-msec intervals may overlap the onset of the BCR, a biphasic 8-pulse stimulation with 2-msec intervals is recommended as the optimal stimulation paradigm to monitor intraoperative BCRs in infants.