A catheter based method to activate urethral sensory nerve fibers

PURPOSE: The ability to control bladder activity would provide a valuable tool to assist individuals with neurological disorders or spinal cord injury (SCI). Recent studies in animal models have shown that bladder contractions can be evoked by electrical stimulation of urethral afferent nerves. We developed and validated in cats a minimally invasive method to stimulate electrically the sensory nerve fibers that innervate the urethra. MATERIALS AND METHODS: The urethra was stimulated electrically along its length via a catheter mounted circumferential electrode in 6 cats. The urethra was similarly stimulated in a male individual with complete SCI. RESULTS: Robust bladder contractions were generated via intraurethral electrical stimulation in all cat experiments. Peak responses were obtained in the proximal and prostatic urethra. In the individual with SCI bladder contractions were generated via intraurethral stimulation at a position 4 cm distal to the bladder. Responses in cats and the human depended on bladder volume. CONCLUSIONS: To our knowledge this study provides the first documentation of generating bladder contractions via intraurethral electrical stimulation in cats and humans. This method provides a research tool for future studies to investigate these pathways in humans. Preliminary human results suggest that urethral afferent mediated neural pathways demonstrated in animal models exist in humans and support the development of neural prostheses using electrical stimulation of these nerves to restore control of bladder function in individuals with neurological disorders or SCI.     

INNERVATION OF THE STRIATED MUSCLE OF THE MEMBRANOUS URETHRA OF THE MALE DOG

Purpose

To identify the functional innervation of the striated muscle layer of the post-prostatic urethra of male dogs.

Materials and Methods

Detailed anatomic dissection of the pelvic and pudendal nerves was carried out. The pressure and contractile responses to stimulation of these nerves were recorded in vivo and in vitro.

Results

Small branches of the pelvic nerve entered the membranous urethra but passed through the striated muscle to the inner smooth muscle layer. Stimulation of the nerve with 1 msec pulses at 10 Hz produced a slow contraction of the urethra which was unaffected by d-tubocurarine. Pudendal nerve branches entered the striated layer from the caudal end. Stimulation produced a rapid, visible contraction that was abolished by d-tubocurarine. Field stimulation of isolated strips of striated muscle resulted only in rapid, d-tubocurarine sensitive contractions.

Conclusions

The striated muscle of the membranous urethra is innervated exclusively by the pudendal nerve.     

Voiding reflex in chronic spinal cord injured cats induced by stimulating and blocking pudendal nerves

AIMS: To induce efficient voiding in chronic spinal cord injured (SCI) cats. METHODS: Voiding reflexes induced by bladder distension or by electrical stimulation and block of pudendal nerves were investigated in chronic SCI cats under alpha-chloralose anesthesia. RESULTS: The voiding efficiency in chronic SCI cats induced by bladder distension was very poor compared to that in spinal intact cats (7.3 +/- 0.9% vs. 93.6 +/- 2.0%, P < 0.05). In chronic SCI cats continuous stimulation of the pudendal nerve on one side at 20 Hz induced large amplitude bladder contractions, but failed to induce voiding. However, continuous pudendal nerve stimulation (20 Hz) combined with high-frequency (10 kHz) distal blockade of the ipsilateral pudendal nerve elicited efficient (73.2 +/- 10.7%) voiding. Blocking the pudendal nerves bilaterally produced voiding efficiency (82.5 +/- 4.8%) comparable to the efficiency during voidings induced by bladder distension in spinal intact cats, indicating that the external urethral sphincter (EUS) contraction was caused not only by direct activation of the pudendal efferent fibers, but also by spinal reflex activation of the EUS through the contralateral pudendal nerve. The maximal bladder pressure and average flow rate induced by stimulation and bilateral pudendal nerve block in chronic SCI cats were also comparable to those in spinal intact cats. CONCLUSIONS: This study shows that after the spinal cord is chronically isolated from the pontine micturition center, bladder distension evokes a transient, inefficient voiding reflex, whereas stimulation of somatic afferent fibers evokes a strong, long duration, spinal bladder reflex that elicits efficient voiding when combined with blockade of somatic efferent fibers in the pudendal nerves.     

Minimally-invasive electrical stimulation of the pudendal nerve: a pre-clinical study for neural control of the lower urinary tract

AIMS: Electrical stimulation of afferent pudendal nerve fibers can evoke sustained bladder contractions (SBC) in cats, yet evidence of therapeutic efficacy in human subjects is lacking. This pre-clinical study was undertaken to test the hypothesis that robust bladder contractions can be generated with a minimally-invasive needle electrode. MATERIALS AND METHODS: In seven adult cats, triggered electromyographic (EMG) signals from the external anal sphincter (EAS) were used to minimize the needle-to-nerve distance; while reflex bladder contractions were recorded as 20-sec trains of current pulses of varying amplitude (threshold to 10 mA) and frequency (1-100 Hz) were applied to the nerve. This stimulation paradigm was repeated at successively greater needle-to-nerve distances (0.5 cm intervals) and also at different electrode positions along the nerve. RESULTS: Electrophysiological access to the pudendal nerve was consistently achieved, as indicated by the average threshold for EAS activation (0.31+/-0.19 mA). Using different combinations of stimulus amplitude and frequency, robust SBCs were evoked in every experiment. More rostral electrode positions exhibited stimulation amplitudes and corresponding maximum bladder pressures (0.68+/-0.36 mA and 25.3+/-3.5 cmH2O, respectively) that were comparable to those of more invasive stimulation methods. CONCLUSIONS: The needle electrode provides a minimally-invasive approach that will enable the study of reflexes mediated by pudendal afferents in humans, and allow pre-operative testing before implanting a permanent device.     

THE FEMALE URETHRAL SPHINCTER: A MORPHOLOGICAL AND TOPOGRAPHICAL STUDY

Purpose

We reassess the anatomy and topography of the female urethral sphincter system and its innervation in regard to urethra sparing anterior exenteration and other surgical procedures.

Materials and Methods

Anatomical and histological studies were performed on 9 fetal specimens and 4 adult cadavers. Using graphics software the anatomical structures of the true pelvis were reconstructed based on computerized tomography cross sections and digitized histological sections. On the adult cadavers anterior exenteration was performed to study the implications of the isolated urethra and its sphincter mechanism.

Results

Strata of connective tissue were found to divide the smooth muscles of the proximal two-thirds of the female urethra into 3 layers. Computer guided 3-dimensional reconstruction of digitized histological sections showed that thin fibers of the pelvic plexus course to this part of the urethra. The majority of these fibers may be preserved by carefully dissecting the bladder neck and the proximal portion of the urethra, leaving the lateral vaginal walls intact. The striated rhabdosphincter, which is innervated by fibers of the pudendal nerve, was in the caudal third of the urethra.

Conclusions

A well-defined sphincteric structure or sphincter could not be anatomically recognized in the bladder neck region. The majority of rhabdosphincter fibers were found in the middle and caudal thirds of the urethra. Thus, in patients undergoing removal of the bladder neck and part of the proximal portion of the urethra continence can be maintained by the remaining urethral sphincter system, provided that innervation remains essentially intact.     

Inhibition of bladder overactivity by stimulation of feline pudendal nerve using transdermal amplitude-modulated signal (TAMS)

What's known on the subject? and What does the study add? It is known that direct stimulation of pudenal nerve using a cuff electrode can inhibit normal bladder activity. This study further indicates that overactive bladder activity can be inhibited using non‐invasive skin surface electrodes and a transdermal amplitude‐modulated signal (TAMS).

OBJECTIVE

• ? To develop a non‐invasive neuromodulation method targeting the pudendal nerve.

MATERIALS AND METHODS

• ? Bladder overactivity induced by acetic acid (AA) irritation was partially suppressed by electrical stimulation of the pudendal nerve in α‐chloralose anaesthetized cats using a transdermal amplitude‐modulated signal (TAMS).

RESULTS

• ? During cystometrography (CMG), intravesical infusion of 0.25% AA significantly decreased the mean (se ) bladder capacity to 28.8 (5.9)% of the capacity measured during saline infusion.
• ? The TAMS stimulation inhibited AA‐induced bladder overactivity at 5, 7 and 10 Hz, and significantly increased the mean (se ) bladder capacity to 61.8 (9.9)%, 51.3 (14.5)%, 53.6 (14.9)%, respectively, of the control capacity during saline infusion, whereas stimulation at 20–40 Hz had no effect.
• ? Under isovolumetric conditions at a bladder volume ranging between 130 to 160% of the bladder capacity measured during AA infusion, TAMS stimulation at all frequencies (5–40 Hz) significantly suppressed the irritation‐induced rhythmic bladder contractions, reduced the area under the bladder pressure curve, and decreased the frequency of bladder contractions. However, the amplitude of rhythmic bladder contractions was only significantly decreased at stimulation frequencies of 5–20 Hz.
• ? At bladder volumes above the AA control capacity, TAMS stimulation with frequencies of 20–30 Hz had an excitatory effect, resulting in large amplitude (>25 cmH₂O) bladder contractions.

CONCLUSIONS

• ? TAMS stimulation targeting the cat pudendal nerve can inhibit C‐fibre afferent‐mediated bladder overactivity.
• ? Thus, clinical research seems warranted to explore the usefulness of this technology for patients with overactive bladder symptoms.

     

Signalstabilit?t als Grundvoraussetzung f��r kontinuierliches intraoperatives Neuromonitoring

Background

Postoperative recurrent laryngeal nerve (RLN) palsy is a well-known and dreaded complication of thyroid surgery. Continuous intraoperative neuromonitoring (CIONM) has been developed in order to provide an effective real-time surveillance of the RLN to its full extent and to detect subtle changes in nerve conductivity. A key requirement for a reliable interpretation of CIONM is signal stability.

Patients and methods

In a prospective randomized controlled pilot study 24 patients corresponding to 30 nerves at risk (NaR) were included to compare a newly developed, flexible, saxophone-shaped backstrap electrode for vagal stimulation (16?NaR) to a commercially available CE-marked cylindrical and rigid electrode (14?NaR). Electrode applicability, safety and signal stability were analyzed by assessment of electrode implantation times, stimulation currents, EMG amplitudes and electrode displacement rates.

Results

Implantation and extraction was significantly faster and easier with the saxophone-shaped backstrap electrode. Accidental electrode displacement occurred up to eight times per operation when applying the cylindrical electrode, while a total of two displacements resulted using the backstrap electrode in this study. Stimulation currents necessary for supramaximal RLN stimulation were significantly lower using the newly developed electrode. At the same time, significantly greater stable EMG amplitudes resulted using the new saxophone-shaped electrode. No RLN palsy occurred during the study.

Conclusions

According to the data, only the saxophone-shaped backstrap electrode provided the signal stability required for CIONM. The closed electrode geometry with isolated contacts for nerve stimulation and defined current entry provide the prerequisites required for reliable continuous intraoperative neuromonitoring.     

Ipsilaterality of motor innervation of canine urethral sphincter

The functional activity of the sphincter muscle of the urethra is known to be controlled largely by the hypogastric and pudendal nerves. It remains unknown, however, whether innervation of the muscle by these peripheral nerves is ipsi- or bilateral. In an attempt to answer this question urethral closure pressure was determined simultaneously in the anterior, posterior, right and left portions of urethral wall in dogs. The pressure measurements were stereographed with the aid of a computer (stereo-UPP) and by this means the effect of unilateral section or electrical stimulation of hypogastric and pudendal nerves on the intraurethral pressure profile was analyzed. Unilateral section or electrical stimulation of the hypogastric nerve, distal to its division, produced a fall and a rise primarily in proximal intraurethral pressure, respectively, in all four directions. There was no significant difference in this response between the involved and uninvolved sides. Unilateral section of the pudendal nerve resulted in a fall primarily in distal intraurethral pressure in all four directions. No significant difference was present between the injured and noninjured sides. In contrast, electrical stimulation of the pudendal nerve distal to the point of its division caused a rise in intraurethral pressure in all four directions, with a significantly greater pressor response on the stimulated than on the nonstimulated side. These observations suggest decussating motor innervation of the urethra by the hypogastric nerves and also the possibility of the distal urethra being ipsilaterally innervated by the pudendal nerve.     

Bilateral pudendal afferent stimulation improves bladder emptying in rats with urinary retention

Study Type – Therapy (individual cohort) Level of Evidence 2b What's known on the subject? and What does the study add? Previous study demonstrated that unilateral electrical stimulation of the proximal transected sensory pudental nerve during distention‐evoked voiding contractions significantly improved voiding efficiency. The current study extends previous study from unilateral (UniES) to bilateral (BiES) stimulation of pudental afferent nerve fibres to determine whether this approach further enhances the improved voiding efficiency (VE) that we reported previously which unilateral stimulation. Our results show in most instances BiES consistently generated more efficient bladder emptying than did UniES but these differences were not significant.

OBJECTIVE

• ? To determine whether bilateral electrical stimulation (BiES) of the transected pudendal sensory nerves could further enhance the voiding efficiency beyond that produced by unilateral electrical stimulation (UniES) of transected pudendal afferents in rats with urinary retention.

MATERIALS AND METHODS

• ? The efficiency of bladder emptying with either UniES or BiES of pudendal nerve afferents was measured after acute bilateral transection of the sensory branch of the pudendal nerve.
• ? The effects of UniES and BiES on voiding in a partially denervated bladder and acute spinal transection, respectively, were determined.

RESULTS

• ? The voiding efficiency (VE) was reduced from 69 to 22% after bilateral transection of the sensory branch of the pudendal nerve. UniES or BiES increased the VE to 49–62%.
• ? Although in most instances BiES consistently generated more efficient bladder emptying than did UniES, these differences were not significant.
• ? Both UniES and BiES increased VE after unilateral pelvic nerve transection, demonstrating efficacy in a partially denervated bladder.
• ? The enhancement of VE by either UniES or BiES was preserved after acute T₉–T₁₀, demonstrating the spinal origin of this augmenting reflex.

CONCLUSIONS

• ? The results of the present study are consistent with an essential role for pudendal sensory feedback in efficient bladder emptying, and unilateral and bilateral electrical activation of pudendal nerve afferents are equally efficient in improving bladder emptying in an animal model of urinary retention.
• ? This could provide an approach to improve bladder emptying in patients with non‐obstructive urinary retention.

     

Long-term efficacy of electrical pudendal nerve stimulation for urgency–frequency syndrome in women

Introduction and hypothesis

Electrical pudendal nerve stimulation (EPNS) was developed by combining the advantages of pudendal neuromodulation (PNM) and percutaneous tibial nerve stimulation (PTNS) and incorporating the technique of deep insertion of long acupuncture needles. The purpose of this study is to show the long-term efficacy of EPNS in treating urgency–frequency syndrome (UFS) in women.

Methods

One hundred and six consecutive female UFS patients were enrolled and treated with EPNS. Long acupuncture needles were deeply inserted into four sacral points and electrified to stimulate the pudendal nerves. Evaluation of therapeutic effects was based on a questionnaire (including questions on storage, voiding, and postmicturition symptoms). Patients with ≥50 % posttreatment symptom improvement were followed up for at least 60 months.

Results

Complete resolution and ≥50 % improvement rate were 42.5 % and 85.8 %, respectively, in the 106 patients after a mean of 21.2 sessions of EPNS treatment. Of the 91 patients with ≥50 % posttreatment improvement, 62 (29 with complete resolution, 15 with marked improvement, and 18 with moderate improvement) were available for follow-up at 60–126 (mean 99.5; median 98) months after the end of EPNS treatment. Of these 62 patients, 35 maintained the posttreatment effect, 18 changed from better to complete resolution, and seven changed back to <50 % improvement; only four of whom changed to <25 % improvement.

Conclusions

EPNS combines the advantages of PNM (better effect) and PTNS (minimally invasive, easily applicable, and well tolerated) in treating UFS. It has a good long-term therapeutic effect on UFS in women.     

Peripheral nerve stimulation by ‘sandwich’ paddle leads: technical note

Background

Recently, there has been a burgeoning interest in the utility of peripheral nerve stimulation (PNS) for a variety of chronic focal neuropathic, musculoskeletal and visceral pain conditions. If the source of pain is directly related to a single peripheral nerve, surgical exposure and placing a paddle lead on the nerve are most effective.

Methods

In this report, we describe a novel technique that optimizes the peripheral nerve stimulation by two paddle leads placed on either side of the nerve with their stimulating surfaces in contact with the nerve. After appropriate prepping and draping, the selected nerve is localized and circumferentially dissected free from the adjacent soft tissue. There should be enough length of nerve to accommodate two On-Point quadripolar leads (Medtronic, MN) along the length of the nerve in the same direction.

Results

This ‘sandwich’ technique provides a wider interface of contacts with nerve fibers. It reduces the chance of migration and provides an opportunity for ‘crosstalk.’

Conclusion

In selected cases where an open surgical PNS lead needs to be placed, the ‘sandwich’ technique can be used to augment the stimulation without additional morbidity. Although occasionally used in practice, this technique is still unreported.     

Cost-utility of maximal safe resection of WHO grade II gliomas within eloquent areas

Background

Despite the growing use of intraoperative electrical stimulation (IES) mapping for resection of WHO grade II gliomas (GIIG) located within eloquent areas, some authors claim that this is a complex, time-consuming and expensive approach, and not well tolerated by patients, so they rely on other mapping techniques. Here we analyze the health related quality of life, direct and indirect costs of surgeries with and without intraoperative electrical stimulation (IES) mapping for resection of GIIG within eloquent areas.

Methods

A cohort of 11 subjects with GIIG within eloquent areas who had IES while awake (group A) was matched by tumor side and location to a cohort of 11 subjects who had general anesthesia without IES (group B). Direct and indirect costs (measured as loss of labor productivity) and utility (measured in quality adjusted life years, QALYs), were compared between groups.

Results

Total mean direct costs per patient were $38,662.70 (range $19,950.70 to $61,626.40) in group A, and $32,116.10 (range $22,764.50 to $46,222.50) in group B (p?=?0.279). Total mean indirect costs per patient were $10,640.10 (range $3,010.10 to $86,940.70) in group A, and $48,804.70 (range $3,340.10 to $98,400.60) in group B (p?=?0.035). Mean costs per QALY were $12,222.30 (range $3,801.10 to $47,422.90) in group A, and $31,927.10 (range $6,642.90 to $64,196.50) in group B (p?=?0.023).

Conclusions

Asleep-awake-asleep craniotomies with IES are associated with an increase in direct costs. However, these initial expenses are ultimately offset by medium and long-term costs averted from a decrease in morbidity and preservation of the patient’s professional life. The present study emphasizes the importance to switch to an aggressive and safer surgical strategy in GIIG within eloquent areas.     

Sacral neuromodulation for lower urinary tract dysfunction

Objectives

To review the technique, indications, results and working mechanisms of sacral neuromodulation (SNM) for lower urinary tract dysfunction.

Methods

The available literature on SNM for lower urinary tract dysfunction was searched. Based on the information available in the literature and also based on personal experience, the urological indications, technique, mechanisms of action and results of SNM are presented and discussed.

Results

SNM for lower urinary tract dysfunction involves stimulation of the 3rd sacral nerve with an electrode implanted in the sacral foramen and connected to a pulse generator. The technique is accepted by the FDA since 1997. Currently, SNM for lower urinary tract dysfunction has been successfully used in about 26,000 patients with various forms of lower urinary tract dysfunction, including urgency, frequency and urgency incontinence as well as non-obstructive urinary retention. The actual procedure of SNM consists of a minimal invasive technique and is effective in about 70% of the patients who have been implanted with a permanent system. Also, in pelvic pain, interesting results have been described. SNM modulates the micturition reflexes at different levels in the central nervous system.

Conclusions

Sacral neuromodulation is a safe and effective therapy for various forms of lower urinary tract dysfunction, including urgency, frequency and urgency incontinence as well as non-obstructive urinary retention. It should be the first choice after failure of maximal conservative therapy.     

Laparoscopic implantation of electrodes for bilateral neuromodulation of the pudendal nerves and S3 nerve roots for treating pelvic pain and voiding dysfunction

Introduction and Hypothesis

The objective of this video is to describe the technique for laparoscopic implantation of electrodes for bilateral neuromodulation of S3 and pudendal nerves. We report a successful case of a 48-year-old woman with spina bifida occulta referred with a 14-year history of intense acyclic pelvic pain, urinary hesitancy, and intermittent flow refractory to various conservative measures.

Methods

The procedure began with the removal of two previously placed InterStims. A quadripolar electrode was then laparoscopically inserted into Alcock’s canal and attached to the pelvic pectineal line. Another lead was placed juxtaneurally to S3. Lead contacts were then exteriorized, and the peritoneum closed. The same procedure was then performed on the contralateral side. The leads were connected to a 16-pole rechargeable pulse generator. Postoperatively, the patient developed an acute dissection and partial thrombosis of the external iliac artery, which was treated endovascularly.

Results

Complete pain resolution was observed with simultaneous S3 and pudendal stimulation, with pudendal stimulation turned off for voiding.

Conclusions

We conclude that laparoscopic implantation of neuromodulation electrodes allows simultaneous stimulation of S3 and pudendal nerves, providing more programming options and possibly increasing success rates in complex pelvic floor dysfunction cases.

     

Electrophysiological evaluation of the pudendal nerve and urethral innervation in female stress urinary incontinence

Introduction and hypothesis

Although still a matter of debate, stress urinary incontinence (SUI) may be accompanied by damage to urethral and pelvic floor innervations, thus promoting dysfunctions of the urethral support and sphincteric closure mechanisms. The aim of this study was to analyze the pelvic floor and urethral innervations through pelvic electrophysiological tests to identify whether neurological alterations interfere with urinary continence and urethral functional activity.

Methods

This prospective study included 52 women, 33 with clinically and urodynamically proven SUI and 19 continent volunteers matched for age, height, parity, and number of vaginal deliveries by the propensity score method. The patients were divided according to the severity of urinary loss evaluated by measuring abdominal leak point pressure (ALPP). Pudendal nerve terminal motor latency (PNTML), pudendal somatosensory evoked potential (SSEP) latencies, urethral and clitoral sensory thresholds, and urethroanal reflex latency were tested.

Results

SUI and control subjects did not differ in PNTML, SSEP latency, and clitoral sensory thresholds. However, reduced responsiveness to urethral electrosensitivity and prolonged urethroanal reflex latency were detected in most incontinent patients. In addition, urethral electrosensitivity was altered in suspected intrinsic sphincteric dysfunction.

Conclusions

Urethral afferent pathways can be altered in women with SUI and may play an important role in evoking intrinsic sphincteric dysfunction.     

Pudendal nerve block in HDR-brachytherapy patients: do we really need general or regional anesthesia?

Purpose

In male patients, the pudendal block was applied only in rare cases as a therapy of neuralgia of the pudendal nerve. We compared pudendal nerve block (NPB) and combined spinal-epidural anesthesia (CSE) in order to perform a pain-free high-dose-rate (HDR) brachytherapy in a former pilot study in 2010. Regarding this background, in the present study, we only performed the bilateral perineal infiltration of the pudendal nerve.

Methods

In 25 patients (71.8 ± 4.18 years) suffering from a high-risk prostate carcinoma, we performed the HDR-brachytherapy with the NPB. The perioperative compatibility, the subjective feeling (German school marks principle 1–6), subjective pain (VAS 1–10) and the early postoperative course (mobility, complications) were examined.

Results

All patients preferred the NPB. There was no change of anesthesia form necessary. The expense time of NPB was 10.68 ± 2.34 min. The hollow needles (mean 24, range 13–27) for the HDR-brachytherapy remained on average 79.92 ± 12.41 min. During and postoperative, pain feeling was between 1.4 ± 1.08 and 1.08 ± 1.00. A transurethral 22 French Foley catheter was left in place for 6 h. All patients felt the bladder catheter as annoying, but they considered postoperative mobility as more important as complete lack of pain. The subjective feeling was described as 2.28 ± 0.74. Any side effects or complications did not appear.

Conclusions

Bilateral NPB is a safe and effective analgesic option in HDR-brachytherapy and can replace CSE. It offers the advantage of almost no impaired mobility of the patient and can be performed by the urologist himself. Using transrectal ultrasound guidance, the method can be learned quickly.     

Ulnar Nerve Innervation of the Triceps Muscle: Real or Apparent? An Anatomic Study

Background

Since the 18th century, the existence of ulnar nerve innervation of the medial head of the triceps brachii muscle has been controversial. The evidence for or against such innervation has been based on macroscopic dissection, an unsuitable method for studying intraneural topography or intramuscular branching. The study of smaller specimens (embryos or fetuses) by means of serial histologic sections may resolve the controversy.

Questions/Purposes

Using fetal specimens and histology we determined the contributions of the ulnar and radial nerves to innervation of the triceps brachii muscle.

Methods

We histologically examined 15 embryonic and fetal arms. Radial nerve branches obtained from six adult arms were analyzed immunohistochemically to determine motor fiber content.

Results

The medial head of the triceps brachii muscle was always innervated by the radial nerve (ulnar collateral branch). The branches seeming to leave the ulnar nerve at elbow level were the continuation of the radial nerve that had joined the ulnar nerve sheath via a connection in the axillary region. Immunohistochemistry revealed motor and nonmotor fibers in this radial nerve branch.

Conclusions

A connection between the radial and ulnar nerves sometimes may exist, resulting in an apparent ulnar nerve origin of muscular branches to the medial head of the triceps, even though in all our specimens the fibers could be traced back to the radial nerve.

Clinical Relevance

Before performing or suggesting new muscle and nerve transpositions using this apparent ulnar innervation, the real origin should be confirmed to avoid failure.     

Bilateral thoracoscopic splanchnicectomy for pain in patients with chronic pancreatitis impairs adrenomedullary but not noradrenergic sympathetic function

Background

Bilateral thoracoscopic splanchnicectomy (BTS) is a well-known technique to alleviate intractable pain in patients with chronic pancreatitis. BTS not only disrupts afferent fibers from the pancreas that mediate pain but also postganglionic sympathetic fibers, which originate in segments T5–T12 and which innervate the vasculature of the liver, pancreas, and the adrenal gland. The purpose of this study was to assess whether and how BTS affects sympathetic noradrenergic and adrenomedullary function in patients with chronic pancreatitis.

Methods

Sixteen patients with chronic pancreatitis for at least 1?year underwent autonomic function testing before and 6?weeks after BTS for intractable pain. Testing was performed during supine rest and during sympathetic stimulation when standing.

Results

Supine and standing systolic and diastolic blood pressure were significantly lower post-BTS compared with pre-BTS (P?=?0.001). One patient showed orthostatic hypotension after BTS. Baseline plasma norepinephrine levels and plasma norepinephrine responses to sympathetic activation during standing were not reduced by BTS. In contrast, supine plasma epinephrine levels and responses during standing were significantly reduced (P?Conclusions BTS for pain relief in patients with chronic pancreatitis reduced adrenomedullary function, due to disruption of the efferent sympathetic fibers to the adrenal gland. BTS did not affect noradrenergic sympathetic activity, although blood pressure was lower after the sympathectomy.     

Magnetic Resonance Imaging After Intraurethral Collagen Injected for Stress Urinary Incontinence

Purpose

Magnetic resonance imaging (MRI) was performed to evaluate the results of intraurethral collagen injected for stress urinary incontinence.

Materials and Methods

A total of 32 women underwent MRI of the pelvis at a median of 12 months after the last injection. The appearance, volume and position of the intraurethral collagen were assessed by 1 radiologist blinded to the outcome, and these findings were compared to clinical data to identify predictive features of success.

Results

Intraurethral collagen was easily imaged by MRI and appeared as a hyperintense focus within the wall of the urethra. Neither volume nor position of retained intraurethral collagen was predictive of clinical outcome (p = 0.80 and p = 0.32, respectively). The volume of injected intraurethral collagen strongly correlated with the retained volume in clinically successful and failed cases (Pearson's r = 0.64 and r = 0.90, respectively). No evidence of local or remote pathological conditions resulting from intraurethral collagen injection was identified.

Conclusions

The position and volume of intraurethral collagen were not predictive of clinical outcome. While MRI is not recommended for routine investigation, it is an excellent research modality for assessing the fate of intraurethral collagen injection.