Long-term follow up of dorsal root entry zone lesions in brachial plexus avulsion

The long-term results of 44 patients who underwent dorsal route entry zone (DREZ) lesioning for pain secondary to brachial plexus avulsion are reported with a mean clinical follow up period of 63 months. The postoperative analgesic effect was judged by the patients as being good (greater than 75% pain reduction), fair (25-75% pain reduction), or poor (0-25% pain reduction). With these criteria 35 patients (77%) had continuing good (30 cases, 68%) or fair (five cases, 11%) pain relief at the time of final follow up. Eight cases (18%) had persisting neurological deficits, although these were generally mild. DREZ thermocoagulation is an effective procedure for relieving deafferentation pain. The analgesic effect which is produced in the early postoperative period seems to be maintained in the long-term.     

Preservation of pudendal afferents in sacral rhizotomies

OBJECTIVE: To assess the effectiveness of pudendal afferent mapping as a tool to minimize the risk of postoperative bowel, bladder, and sexual dysfunction in patients undergoing selective posterior rhizotomies in whom the S2 roots are candidates for rhizotomy. METHODS: One-hundred fourteen children with the diagnosis of cerebral palsy and debilitating spasticity were selected to undergo selective posterior rhizotomies at New York University Medical Center during 1991 through 1995. There were 72 male and 42 female patients with a mean age of 3.8 years. At the time of surgery, none of the patients had clinically relevant bladder dysfunction. Dorsal root action potentials were recorded intraoperatively to map the distribution of pudendal afferent fibers in S1-S3 roots bilaterally before performing the rhizotomies. RESULTS: Pudendal afferent mapping was successful in 105 of 114 patients. In the majority of these patients (56%), the distribution was asymmetrical. S1 roots contributed 4%, S2 roots 60.5%, and S3 roots 35.5% of the overall pudendal afferent activity. The pudendal afferent distribution was often confined to a single level in 18% of the patients or even to a single root in 7.6%. Fifty-six percent of the pathologically responding S2 roots during rhizotomy testing were preserved because of the significant afferent activity, as demonstrated during pudendal mapping. None of the 105 patients so mapped developed long-term bowel or bladder complications. CONCLUSIONS: Pudendal afferent mapping identifies S2 roots that carry a significant number of fibers involved with genital sensation. The preservation of such roots during surgical procedures may be important for sexual function and may also contribute to decreasing postoperative bladder and bowel disturbances.     

Dorsal horn cells connected to the lissauer tract and their relation to the dorsal root potential in the rat

We have examined the role of dorsal horn cells that respond to Lissauer tract stimulation in regulating primary afferent depolarization (PAD). PAD was monitored by recording the dorsal root potential (DRP) in the roots of the lumbar cord. Recordings were made of the discharges of Lissauer tract-responsive cells, and their discharges were correlated with the DRPs occurring spontaneously and those evoked by stimulation. Electrical microstimulation of the Lissauer tract (<10 microA; 200 micros) was used to activate the tract selectively and evoke a characteristic long-latency DRP. Cells that were excited by Lissauer tract stimulation were found in the superficial laminae of the dorsal horn. They exhibited low rates of ongoing discharge and responded to Lissauer tract stimulation typically with a burst of impulses with a latency to onset of 5.6 +/- 2.7 ms (mean +/- SD) and to termination of 13.6 +/- 4.1 ms (n = 105). Lissauer tract-responsive cells in L5 were shown to receive convergent inputs from cutaneous and muscle afferents as they responded to stimulation of the sural nerve (100%, n = 19) and the nerve to gastrocnemius (95%, n = 19). The latency of the response to sural nerve stimulation was 3.7 +/- 1.5 ms and to gastrocnemius nerve stimulation, 8.3 +/- 3.6 ms. Stimulation through a microelectrode at a depth of 1.5 mm in the sensorimotor cortex (100 microA, 200 micros) evoked a response in 17 of 31 Lissauer tract-responsive cells (55%) with a latency to onset of 21.9 +/- 2.8 ms (n = 17). Stimulation of the sural nerve, nerve to gastrocnemius or sensorimotor cortex was shown to depress the response of Lissauer tract-responsive cells to a subsequent Lissauer tract stimulus. The ongoing discharges of Lissauer tract-responsive cells were correlated to the spontaneous DRP using spike-triggered averaging. Of 123 cells analyzed in this way, 117 (95%) were shown to be correlated to the DRP. In addition, the peaks of spontaneous negative DRPs in spinally transected animals were detected in software. Perievent time histograms triggered from these peaks showed the discharge of Lissauer tract-responsive cells to be correlated to the spontaneous DRPs in 57 of 62 cells (92%) recorded. We conclude that these data provide compelling evidence that the Lissauer tract, and the dorsal horn cells that it excites, mediate the PAD evoked from multiple neural pathways.     

Selective peripheral neurotomy of the hamstring branches of the sciatic nerve in the treatment of spastic flexion of the knee. Apropos of a series of 11 patients

BACKGROUND: A series of 11 patients (9 adults and 2 children) were operated on by selective peripheral neurotomy for spastic knee in flexion. The objective of surgery was to restore bipodal stance and therefore walking for the adult patients and to improve walking for the diplegic children. METHODS: Spasticity was secondary to stroke or cranial trauma for the adult patients. The two children presented with Little disease. The delay between onset and surgery was on the average of 2 years. All the patients had a passive flexum of the knee of 20 degrees, and an excessive spasticity of the hamstrings (average Held score of 4.55). Peripheral selective neurotomies consist of a partial section of the spastic muscle's motor fascicles. The partial section concerns the afferent fibers to the spinal cord whose interruption leads to the disappearance of spasticity. The section also involves the motoneurones' axons and thus leads to partial denervation. RESULTS: The spasticity of the treated muscles disappeared in the 11 patients. Average follow-up was 16 months. The neurotomies led to improvement of walking without splint for 3 walking patients, and restored walking with a splint for 5 patients. One patient failed to walk. The two children had a dramatic improvement of their walk. CONCLUSION: Our results incite us to increasingly indicate this type of neurotomy in the treatment of the spastic lower limb.     

The accessory optic fiber system of the golden hamster with special reference to retinohypothalamic projection

The hamster accessory optic fiber system has been investigated with the use of de Olmos-Ingram and Fink-Heimer silver methods following the production of unilateral ocular enucleation. It was found that this fiber system consists of both crossed and uncrossed inferior and superior fasciculi. The fibers of the inferior fasciculus (anterior accessory optic tract) run along the medial edge of the cerebral peduncle and terminate within the medial terminal nucleus of the accessory optic system. The fibers of the superior fasciculus (posterior accessory optic tract) leave the main optic tract, pass superficially over the medial geniculate nucleus and the cerebral peduncle; they synapse within the dorsal, the lateral and the medial terminal accessory optic nuclei. The presence of a retinohypothalamic tract could not be confirmed.     

Effect of systemic tetracycline and amoxicillin on inflammatory root resorption of replanted dogs'' teeth

Upper motor neuron lesion in adults is usually associated with spasticity and "extensor toe sign" on plantar stimulation (extensor plantar response). There are various methods of eliciting this sign including the classic method by Babinski. Other methods produce this response when the area of reflexogenic zone is increased due to upper motor neuron lesion. There are varying reports of Babinski positivity in spastic cerebral palsy. This study was undertaken to assess the sensitivity of different methods of eliciting "extensor toe sign." An attempt has also been made to correlate the severity of spasticity with the combined "extensor toe sign" positivity by various methods and with the increase in reflexogenic zone. Eighty-one children with spastic cerebral palsy were examined. Twelve had hemiplegia; therefore, a total of 150 limbs were tested. "Extensor toe sign" was elicited by 12 different methods in each patient. The sensitivity of each method was calculated and compared with each other one. The assessment of spasticity was done using the Ashworth Tone Scale. The severity of spasticity was correlated with "extensor toe sign" positivity using various methods. Classic Babinski reflex was positive in 75% of cases, whereas Gonda-Allen sign was positive in 90% of cases followed by Allen-Cleckley (82%), Chaddock (74%), and Cornell (54%). All other signs had sensitivity of less than 30%. There was no increase in sensitivity after combining them. There was significant negative correlation between the spasticity and the combined "extensor toe sign" positivity (by all the methods). This study, therefore, suggests that the majority of patients with spastic cerebral palsy have positive "extensor toe sign." The Gonda-Allen method is more sensitive than the classic Babinski method. A positive "extensor toe sign" is negatively correlated to the degree of spasticity.     

Sprouting of primary afferent fibers after spinal cord transection in the rat

After spinal cord injury, hyper-reflexia can lead to episodic hypertension, muscle spasticity and urinary bladder dyssynergia. This condition may be caused by primary afferent fiber sprouting providing new input to partially denervated spinal interneurons, autonomic neurons and motor neurons. However, conflicting reports concerning afferent neurite sprouting after cord injury do not provide adequate information to associate sprouting with hyper-reflexia. Therefore, we studied the effect of mid-thoracic spinal cord transection on central projections of sensory neurons, quantified by area measurements. The area of myelinated afferent arbors, immunolabeled by cholera toxin B, was greater in laminae I-V in lumbar, but not thoracic cord, by one week after cord transection. Changes in small sensory neurons and their unmyelinated fibers, immunolabeled for calcitonin gene-related peptide, were assessed in the cord and in dorsal root ganglia. The area of calcitonin gene-related peptide-immunoreactive fibers in laminae III-V increased in all cord segments at two weeks after cord transection, but not at one week. Numbers of sensory neurons immunoreactive for calcitonin gene-related peptide were unchanged, suggesting that the increased area of immunoreactivity reflected sprouting rather than peptide up-regulation. Immunoreactive fibers in the lateral horn increased only above the lesion and in lumbar segments at two weeks after cord transection. They were not continuous with dorsal horn fibers, suggesting that they were not primary afferent fibers. Using the fluorescent tracer DiI to label afferent fibers, an increase in area could be seen in Clarke's nucleus caudal to the injury two weeks after transection. In conclusion, site- and time-dependent sprouting of myelinated and unmyelinated primary afferent fibers, and possibly interneurons, occurred after spinal cord transection. Afferent fiber sprouting did not reach autonomic or motor neurons directly, but may cause hyper-reflexia by increasing inputs to interneurons.     

Reconstruction of trajectory of primary afferent collaterals in the dorsal horn of the cat spinal cord, using Golgi-stained serial sections

Using Golgi-stained serial sections obtained at the sacro-caudal levels of the cat spinal cord, it was possible to reconstruct the trajectory of primary afferents. They were classified into two groups: reliable primary afferents directly traced from the dorsal root and probable primary afferents traced from the dorsal funiculus or Lissauer's tract. The diameters of the reliable primary afferents vary from 0.88-1.88 mum. According to their courses, reliable primary afferents as well as probable primary afferents were classified into three groups: the first is distributed to both medial and lateral halves of the dorsal horn, the second to the medial half, and the third to the lateral half. Commissural fibers were also observed among the probable primary afferents. The rostro-caudal and medio-lateral extents of reliable primary afferents are found to be between 250 and 950 mum and 270 and 700 mum respectively, while those of the probable primary afferents were between 125 and 670 mum and 270 and 1,640 mum respectively. These primary afferent fibers are connected with at least two or more laminae of the dorsal horn gray matter.     

Central nervous pain in patients with spinal cord injury. Medical and surgical treatment

About 50% of patients with spinal cord injury suffer from persistent central neurogenic pain. The authors review the case of a patient with traumatic paraplegia who developed persistent central neurogenic pain. The pain was described as burning in the buttock area, icing in the rectum area and as lancinating pain to the lower extremities. The combination of amitryptilin and morphine had a slight, short-term effect, but the pain did not respond to treatment with simple analgetica, dextropropoxyphen or ketobemidone, neither administered alone nor in combination with tricyclic antidepressants, carbamazepine or baclophen. Transcutanous nerve stimulation and acupuncture had no effect. The patient was operated on by means of the computer-assisted dorsal root entry zone (DREZ)-microcoagulation technique 2.5 years after the trauma. This technique is described in brief. The prevalence and classification of neurogenic pain, and possible medical and surgical treatment, are also discussed.     

Distal thigh/arm index as a predictor of success for lumbar sympathectomy

Data from 90 lumbar sympathectomies were reviewed to assess the role of a distal thigh/arm Doppler systolic index (DTAI) and of external magnetic flowmeter (MCBF) measurements for predicting patient outcome following lumbar sympathectomy. The presenting symptoms included impending gangrene, gangrene, rest pain, nonhealing ulcers, and disabling claudication. Of the 90 cases, clinical improvement occurred in 57% of the limbs. Major amputation was not required in 73% of the limbs. The MCBF data showed variability which masked the relationship to the effects of sympathectomy. DTAI test results were significantly related to outcome. For DTAI > 0.6 (57 patients), improvement occurred in 70% of the limbs, with major amputation not required in 86% of the limbs. For DTAI < 0.6 (33 patients), improvement occurred in only 33% of the limbs, and major amputation was not required in 52% of the limbs. The Doppler systolic index has provided a noninvasive measure that can be used in conjunction with good clinical judgment for predicting the outcome of lumbar sympathectomy.     

Vagal, sympathetic and somatic sensory inputs to upper cervical (C1-C3) spinothalamic tract neurons in monkeys

1. Myocardial ischemia activates vagal and sympathetic cardiac afferent fibers. The purpose of this study was to determine a neuro physiological basis for cardiac pain referred to C1-C3 somatic dermatomes. We hypothesized that afferent fibers traveling in vagal or sympathetic nerves transmit nociceptive information to C1-C3 spinothalamic tract (STT) neurons. 2. Electrical stimulation of the left stellate ganglion to excite cardiopulmonary sympathetic afferent fibers increased extracellular activity of 44 of 77 C1-C3 STT neurons examined in 33 anesthetized male monkeys (Macaca fascicularis); responses increased as stimulus strength increased. Additionally, this stimulus inhibited 5 cells, increased/decreased activity of 2 cells, and did not affect 26 cells. 3. Electrical stimulation of the left (ipsilateral) thoracic vagus nerve excited 41 of 78 C1-C3 STT neurons, inhibited 4 neurons, increased/decreased activity of 2 neurons, and did not affect 31 neurons. Responses increased with increasing stimulus strength Contralateral vagal stimulation excited 7 of 39 cells tested, inhibited 4 cells and did not affect 28 cells. 4. Effects of stimulating one or more vagal branches were examined on 22 C1-C3 STT neurons excited by input from left thoracic vagus nerve. Stimulation of the cardiac branch excited 11 of 16 cells tested; stimulation of the recurrent laryngeal nerve excited 11 of 18 cells; stimulation of vagal fibers just rostral to the diaphragm excited 8 of 19 cells. 5. Excitatory somatic receptive fields ranged from small ipsilateral fields to large, sometimes bilateral or noncontinuous fields. Many fields included the ipsilateral neck and/or inferior jaw. Thirty-nine of 74 neurons examined were wide dynamic range (WDR), 21 were high threshold (HT), 6 were low threshold (LT), and 8 did not respond to brushing or noxious pinching of somatic tissues. Most (38 of 39) WDR cells responded to stimulation of the stellate ganglion or vagal fibers, as did 18 of 21 HT cells, 3 of 6 LT cells, and 2 of 8 cells unresponsive to brush or pinch stimuli. 6. Results of this study supported the concept that vagal and/ or sympathetic afferent activation of C1-C3 STT neurons might provide a neural mechanism for referred pain that originates in the heart or other visceral organs but is perceived in the neck and jaw region. Additionally, C1-C3 STT neurons processed sensory information from widespread regions of the body.     

Characterization of mechanosensitive pelvic nerve afferent fibers innervating the colon of the rat

1. Single-unit activity was recorded from S1 sacral dorsal root afferent fibers in the anesthetized rat. A total of 364 afferent fibers were identified by electrical stimulation of the pelvic nerve and subsequently tested for response to colorectal distension (CRD) and urinary bladder distension (UBD). Sixty-seven percent (n = 244) of the fibers were unmyelinated C-fibers and 33% (n = 120) were thinly myelinated A delta-fibers. 2. In three initial experiments, 35 fibers were identified by pelvic nerve stimulation and tested for response only to CRD; none of these fibers responded to CRD. In 20 subsequent experiments, 329 pelvic nerve afferent fibers were tested for response to CRD and UBD. Thirty-four percent (n = 112) of the 329 fibers were unresponsive to noxious CRD (80 mmHg) or to UBD (slow filling < or = 100 mmHg), 44% (n = 146) responded to UBD, 16% (n = 53) responded to CRD, and 6% (n = 18) responded to mechanical stimulation of the anal mucosa. 3. Of the total of 53 pelvic nerve afferent fibers that responded to CRD, 43 (81%) were C-fibers (mean: 1.5 m/s) and 10 (19%) were A delta-fibers (mean: 4.7 m/s). Fifteen of the CRD-sensitive fibers had no resting activity, whereas 38 fibers exhibited some resting activity (mean: 2.6 imp/s). 4. Reproducibility of responses to repeated CRD (80 mmHg, 30s, 10 trials at 4-min intervals) was tested in 17 fibers. In 16, responses to repeated distension were reproducible without evidence of facilitation or inhibition of subsequent responses. One fiber gave greater responses during the 9th and 10th trials. 5. Responses to graded CRD were studied in 44 fibers. All fibers exhibited monotonic, increasing stimulus-response functions < or = 80 mmHg of distension. Thresholds for response of the 44 fibers were determined after extrapolation of the least-squares linear-regression line to the ordinate and varied between 0 and 40 mmHg. Two populations of pelvic nerve afferent fibers in the colon were apparent: low threshold (LT) afferent fibers had a mean threshold of 2.9 mmHg (range: 0-10 mmHg; n = 34) and high threshold (HT) afferent fibers had a mean threshold of 32.6 mmHg (range: 28.0-40.0 mmHg; n = 10). 6. Chemosensitivity to bradykinin (BK) was tested in nine LT fibers. Seven fibers responded to BK (0.1 to 100 micrograms/kg ia) and two fibers did not respond up to 100 micrograms/kg of BK. Responses to BK tested in three fibers were dose dependent.(ABSTRACT TRUNCATED AT 400 WORDS)     

Transneuronal pathways to the vestibulocerebellum

The alpha-herpes virus (pseudorabies, PRV) was used to observe central nervous system (CNS) pathways associated with the vestibulocerebellar system. Retrograde transneuronal migration of alpha-herpes virions from specific lobules of the gerbil and rat vestibulo-cerebellar cortex was detected immunohistochemically. Using a time series analysis, progression of infection along polyneuronal cerebellar afferent pathways was examined. Pressure injections of > 20 nanoliters of a 10(8) plaque forming units (pfu) per ml solution of virus were sufficient to initiate an infectious locus which resulted in labeled neurons in the inferior olivary subnuclei, vestibular nuclei, and their afferent cell groups in a progressive temporal fashion and in growing complexity with increasing incubation time. We show that climbing fibers and some other cerebellar afferent fibers transported the virus retrogradely from the cerebellum within 24 hours. One to three days after cerebellar infection discrete cell groups were labeled and appropriate laterality within crossed projections was preserved. Subsequent nuclei labeled with PRV after infection of the flocculus/paraflocculus, or nodulus/uvula, included the following: vestibular (e.g., z) and inferior olivary nuclei (e.g., dorsal cap), accessory oculomotor (e.g., Darkschewitsch n.) and accessory optic related nuclei, (e.g., the nucleus of the optic tract, and the medial terminal nucleus); noradrenergic, raphe, and reticular cell groups (e.g., locus coeruleus, dorsal raphe, raphe pontis, and the lateral reticular tract); other vestibulocerebellum sites, the periaqueductal gray, substantia nigra, hippocampus, thalamus and hypothalamus, amygdala, septal nuclei, and the frontal, cingulate, entorhinal, perirhinal, and insular cortices. However, there were differences in the resulting labeling between infection in either region. Double-labeling experiments revealed that vestibular efferent neurons are located adjacent to, but are not included among, flocculus-projecting supragenual neurons. PRV transport from the vestibular labyrinth and cervical muscles also resulted in CNS infections. Virus propagation in situ provides specific connectivity information based on the functional transport across synapses. The findings support and extend anatomical data regarding vestibulo-olivo-cerebellar pathways.     

Evaluation of pulmonary afferent fibers in the nucleus tractus solitarius: a horseradish peroxidase and c-fos like immunohistochemical study in the rat

Wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) was injected into the rat lung parenchyma, just beneath the lateral surface of the left upper lobe, in order to demonstrate the pulmonary afferents. This injection resulted in heavy accumulation of labeled fibers in the medial nucleus tractus solitarius (NTS). The labeling in the medial NTS was divided into the ventral and dorsal parts at the level around the obex. Some labeling was found in the commissural and ventrolateral NTS. Further confirmation of the central distribution of these pulmonary afferent fibers was made by the expression of fos-like immunoreactivity (FOS-LI) induced by injection of formalin into the lung. It is concluded that afferents of lung parenchyma terminating predominantly in the medial NTS might come from alveoli and terminal bronchioles, because WGA-HRP and formalin injected into the lung are considered to be confined to the terminal areas of the respiratory tract.     

The function of sensory nerve fibers in lumbar radiculopathy. Use of quantitative sensory testing in the exploration of different populations of nerve fibers and dermatomes

STUDY DESIGN: The function of sensory nerve fibers in patients with lumbar radiculopathy and in control individuals was evaluated using quantitative sensory testing. OBJECTIVES: To investigate the effect of lumbar nerve root compression on different populations of nerve fibers and to explore the function of sensory nerve fibers in neighboring nerve roots not involved in the mechanical compression. BACKGROUND DATA: Results from experimental and clinical studies indicate that chronic compression of lumbar nerve roots affects the large myelinated nerve fibers. The majority of nerve fibers involved in the sensation of pain, however, are small afferent nerve fibers. It is therefore of interest to study the effect of compression on large and small sensory afferent channels. Several authors have elucidated the biochemical interaction between disc tissue and nerve roots. Chemical substances in the epidural space can reach the nerve fibers in nerve roots at the same or neighboring lumbar segments. In this way, fibers not involved in the mechanical compression may be affected. METHODS: The small nerve fibers were studied using tests for thermal thresholds (thermotest), and the large myelinated fibers were studied by vibrametry. Forty-two patients were investigated in the symptomatic and the asymptomatic leg, and the results were compared with those of 21 healthy individuals. RESULTS: The thresholds of cold, warmth, and vibration were significantly increased in the dermatome of the compressed nerve root, indicating that large and small sensory nerve fibers were affected. Further, the thresholds were significantly increased in the neighboring dermatomes in the symptomatic and the asymptomatic leg. CONCLUSION: Large and small sensory afferent nerve fibers are affected in lumbar radiculopathy. The increase in sensation thresholds in the ipsilateral neighboring dermatome and in the dermatomes in the asymptomatic leg indicates that adjacent nerve roots are involved in the pathophysiology of sciatica in patients with lumbar disc herniation.     

A report of the quantitative determination of relative afferent pupillary defect in central retinal vein occlusion

Relative afferent pupillary defect (RAPD) indicates injury to the afferent pupillary nerve fibers anterior to the optic chiasma. The light attenuator composed of 2 optical polarizers was utilized to determine the RAPD quantitatively in 32 cases of central retinal vein occlusion (CRVO). In 13 cases with ischemic CRVO, 77% manifested an RAPD of 0.9 log unit or over and none less than 0.75 log unit. In contrast, among 19 cases with non-ischemic CRVO, 84% showed an RAPD of 0.65 log unit or less and none over 0.75 log unit, suggesting that RAPD was a sensitive index for differentiating ischemic from non-ischemic CRVO.     

Immunoblastic lymphoid hyperplasia resembling a tumour, due to drug hypersensitivity (author''s transl)]

An evaluation of dorsal longitudinal myelotomy in the management of spasticity of the lower limbs has been done in 17 patients. The follow-up has varied from 1 month to over 2 years. Most patients achieved satisfactory relief from spasticity. Eight patients have died after the operation in chronic care hospitals. In all except one, the spasticity had been relieved. Eight out of the nine living patients have benefited from myelotomy. Recurrence of spasticity following the first operation occurred in four patients, two of whom improved after a repeat myelotomy. In the presence of fixed contractures of the hip and knee joints, a satisfactory clinical result may not be obtained after the myelotomy.     

Serum paraoxonase and platelet-activating factor acetylhydrolase in chronic renal failure

PURPOSE: Since clinically apparent varicoceles may affect testicular volume and sperm production, early repair has been advocated. However, repair of the pediatric varicocele with conventional nonmagnified techniques may result in persistence of the varicocele after up to 16% of these procedures. Also testicular artery injury and postoperative hydrocele formation can occur after nonmagnified repair. The microsurgical technique has been successfully completed in a large series of adults with a dramatic reduction in complication and recurrence rates. We report our experience with the microsurgical technique in boys. MATERIALS AND METHODS: A total of 30 boys (average age 15.9 years) underwent 42 microsurgical varicocelectomies (12 bilateral). All patients had a large left varicocele. Indications for repair included testicular atrophy (size difference between testicles of greater than 2 ml.) in 20 boys, pain in 5 and a large varicocele without pain or testicular atrophy in 5. Six boys were referred following failure of conventional nonmicrosurgical techniques. All boys were examined no sooner than 1 month postoperatively (mean followup 12). RESULTS: Preoperative volume of the affected testis averaged 13.0 ml., and an average size discrepancy between testicles of 2.8 ml. was noted before unilateral varicocelectomy. No cases of persistent or recurrent varicoceles were detected, and 1 postoperative hydrocele resolved spontaneously. After unilateral varicocelectomy the treated testes grew an average of 50.1%, while the contralateral testes grew only 23%. Overall, 89% of patients with testicular atrophy demonstrated reversal of testicular growth retardation after unilateral varicocelectomy. In contrast, both testes showed similar growth rates after bilateral varicocelectomy (45% left testis, 39% right testis). CONCLUSIONS: The meticulous dissection necessary to preserve arterial and lymphatic supply, and to ligate all spermatic veins in the pediatric patient is readily accomplished using a microsurgical approach, and results in low recurrence and complication rates. Rapid catch-up growth of the affected testis after microsurgical varicocelectomy suggests that intervention during adolescence is effective and warranted.     

Fusimotor-free spindles in reinnervated muscles of neonatal rats treated with nerve growth factor

Crushing the nerve to the medial gastrocnemius muscle in newborn rats and administering nerve growth factor afterwards results in a reinnervated muscle containing supernumerary muscle spindles. The structure and innervation of 88 spindles in the reinnervated muscles were reconstructed from serial thick and thin transverse sections at 30-35 days after the nerve crush, and compared to those of five control spindles. The spindles consisted of one to four small-diameter encapsulated fibers with features of nuclear chain intrafusal fibers, or infrequently a nuclear bag intrafusal fiber. Some of the spindles were located within a capsule that also contained an extrafusal fiber. Each spindle was innervated by an afferent with features of the primary afferent. The density of secondary afferents was lower in reinnervated muscles than in controls. Endplates were observed on extrafusal fibers in the experimental muscles, attesting to restoration of skeletomotor (alpha) innervation after the nerve crush. However, 78% of the experimental spindles were entirely devoid of efferent innervation. The remainder received either one or two fusimotor (gamma) axons or a skeletofusimotor (beta) axon, compared to the six to eight motor axons that innervated control spindles. The presence of supernumerary spindles composed of fibers that resemble normal intrafusal fibers in the absence of motor innervation suggests that afferents alone can induce the formation and subsequent differentiation of intrafusal fibers in nerve-crushed muscles of neonatal rats. In addition, the paucity of gamma innervation in nerve-crushed muscles suggests that immature gamma neurons are more susceptible than spindle afferents or alpha efferents to cell death after axotomy at birth.     

Ultrasound appearance of gas bubbles in hepatic veins after orthotopic liver transplantation: a phenomenon with consequences?

Neuropathic pain is not well understood. Although central dorsal horn remodelling is likely important in maintaining chronic neuropathic pain, afferent activity from injured nerves or ganglia may initiate these changes. It is suggested, in this review that the peripheral nerve trunk is capable of sustaining a "flare" response as observed in injured skin and other tissues. The injury response may be associated with local vasodilatation, plasma extravasation and the generation of painful local afferent activity sustained by locally originating peptidergic fibers (nervi nervorum). These fibers contain substance P, calcitonin gene-related peptide and other peptides that have been linked to nociceptive transmission. Manipulation of the local injury response of the nerve trunk by pharmacologic means may provide one strategy in the treatment of neuropathic pain.