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Introduction: The technique of radiofrequency neurotomy (RFN) of the facet joints has been used for decades to treat persistent low back pain to good effect in carefully selected patients. Traditionally, the target is the medial branches of the dorsal root supplying the facet joint. An alternative denervation target is the facet joint capsule. Capsule‐targeting techniques may spare the multifidus muscle, a possible unintended target of traditional RFN that is thought to be important in recovering from low back pain, and have shown promising results. Methods: A modified RFN technique that targets the capsule and spares the multifidus (multifidus‐sparing RFN) is described here, along with a brief report of its application in patients with symptomatic facet joint low back pain as compared to traditional medial branch RFN (MBRF). Results: Over a 2‐year period, a total of 401 initial multifidus‐sparing RFN and 94 initial MBRF procedures were performed on patients attending a multidisciplinary pain clinic. The proportion of repeat procedures was similar: 28.4% of multifidus‐sparing procedures and 23.4% of MBRF procedures. The median repeat interval was 12 months for both groups and interquartile range was 10 months (8–18 months) for multifidus‐sparing RFN and 4 months (11–15 months) for MBRF. Effectiveness and safety profiles appear to be similar, although limited, retrospective outcome information prevented robust analysis. Conclusion: Multifidus‐sparing RFN represents an intriguing technique to denervate the facet joint pain generator while maintaining normal multifidus function. Further study is warranted, particularly in order to identify the appropriate patient criteria and long‐term outcomes. [ABSTRACT FROM AUTHOR]

Background: Cervical selective nerve root blocks (C‐SNRBs) maintain utility for presurgical planning in patients with cervical radiculopathy. Traditional fluoroscopic or stationary computed tomography (CT)‐guided methods have been associated with complications, including catastrophic neurologic insults, while ultrasound guidance has been investigated based on its theoretical advantages. Maximizing patient safety by obtaining superior anatomic and procedural details promotes the exploration for better alternative guidance. Methods: We describe a novel approach of posterolateral (PL) extraforaminal (EF) C4 SNRB using cone beam–based CT (CBCT)/fluoroscopy, which was performed on 3 separate occasions for 1 patient with suspected right C4 radiculopathy for presurgical evaluation. CBCT/fluoroscopy uniquely provides the function of both CT and fluoroscopy using a C‐arm machine. It allows precise 3‐dimensional needle planning and sophisticated 2‐dimensional needle guidance, while ensuring tight needle control and detailed monitoring of contrast spread. Results: A successful right C4 SNRB was repeatedly achieved, as evidenced by postprocedural paresthesias over the C4 dermatomal distribution and periradicular contrast spread. Additionally, the patient reported symptomatic relief (with regard to pain scores and neck range of motion), leading to cancelation of his surgical plan. Conclusion: We propose the PL‐EF approach as the safest protocol for C‐SNRBs. When compared with fluoroscopy or CT, CBCT/fluoroscopy is an advanced imaging system that provides superior anatomic neurovascular detail, while offering precise needle control, contrast media monitoring, and easy operation in an office setting. These advanced features support it as the ideal guidance method for maximizing both the safety and efficiency of the PL‐EF C‐SNRB approach. However, the claimed advantages cannot be concluded without increasing its accessibility to pain specialists and conducting a prospective study with a large sample size. [ABSTRACT FROM AUTHOR]

Cebranopadol (trans-6'-fluoro-4',9'-dihydro-N,N-dimethyl-4-phenyl-spiro[cyclohexane-1,1'(3'H)-pyrano[3,4-b]indol]-4-amine) is a novel analgesic nociceptin/orphanin FQ opioid peptide (NOP) and classical opioid receptor (MOP, DOP, and KOP) agonist with highly efficacious and potent activity in a broad range of rodent models of nociceptive, inflammatory, and neuropathic pain as well as limited opioid-type side effects such as respiratory depression. This study was designed to explore contribution and interaction of NOP and classical opioid receptor agonist components to cebranopadol analgesia in the rat spinal nerve ligation (SNL) model. Assessing antihypersensitive activity in SNL rats intraperitoneal (IP) administration of cebranopadol resulted in ED50 values of 3.3 and 3.58 μg/kg in two independent experiments. Pretreatment (IP) with J-113397 (4.64 mg/kg) a selective antagonist for the NOP receptor or naloxone (1 mg/kg), naltrindole (10 mg/kg), or nor-BNI (10 mg/kg), selective antagonists for MOP, DOP, and KOP receptors, yielded ED50 values of 14.1, 16.9, 17.3, and 15 μg/kg, respectively. This 4-5 fold rightward shift of the dose-response curves suggested agonistic contribution of all four receptors to the analgesic activity of cebranopadol. Combined pretreatment with a mixture of the antagonists for the three classical opioid receptors resulted in an 18-fold potency shift with an ED50 of 65.5 μg/kg. The concept of dose equivalence was used to calculate the expected additive effects of the parent compound for NOP and opioid receptor contribution and to compare them with the observed effects, respectively. This analysis revealed a statistically significant difference between the expected additive and the observed effects suggesting intrinsic synergistic analgesic interaction of the NOP and the classical opioid receptor components of cebranopadol. Together with the observation of limited respiratory depression in rats and humans the synergistic interaction of NOP and classical opioid receptor components in analgesia described in the current study may contribute to the favorable therapeutic index of cebranopadol observed in clinical trials. [ABSTRACT FROM AUTHOR]

Aim: To examine long-term outcomes of selective dorsal rhizotomy (SDR) 10 to 17 years after surgery.Method: Participants who underwent SDR had spastic diplegic cerebral palsy (CP), completed baseline gait analysis, and were 16 to 25 years old at follow-up. Non-SDR participants (i.e. controls) were matched on important clinical parameters at baseline but did not undergo SDR. All study participants completed six surveys assessing pain, quality of life, participation, function, and mobility. Treatment history for lower extremity surgery and antispasticity injections was tabulated. A subset of each study group returned for three-dimensional gait analysis, including kinematics, metabolic energy cost, and physical examination. Gait Deviation Index (GDI) was calculated to measure gait quality.Results: The study cohort had 24 participants with SDR and 11 without SDR. Of these, 13 patients with SDR (five males, eight females; median [IQR] age 17y 2mo [16y 8mo-17y 9mo]) and eight without SDR (three males, five females; median [IQR] age 19y 2mo [17y 3mo-21y 11mo]) completed baseline and follow-up gait analysis. Spasticity significantly decreased in those with SDR (p<0.05). Gait Deviation Index improved more in participants without SDR than those with SDR (Δnon-SDR =12.8 vs ΔSDR =9.1; p=0.01). Compared with the SDR group, participants without SDR underwent significantly more subsequent interventions (p<0.05).Interpretation: Patients in both the SDR and non-SDR groups showed improved gait quality more than 10 years after surgery. Participants without SDR had a larger improvement in gait pathology but underwent significantly more intervention. There were no differences between groups in survey measures. These results suggest differing treatment courses provide similar outcomes into early adulthood.What This Paper Adds: Selective dorsal rhizotomy (SDR) and non-SDR groups had significant improvement in gait pathology over time. The non-SDR group had significantly better gait compared with the SDR group at follow-up. The groups had similar levels of energy cost, pain, and quality of life. Non-SDR participants underwent significantly more orthopaedic surgery and antispasticity injections than SDR participants. Use of a clinically similar control group highlights that different treatment courses may result in similar outcomes into young adulthood. [ABSTRACT FROM AUTHOR]

Spinal nerve root enhancement in pediatric patients is generally nonspecific, and clinical and laboratory correlation is essential. Nerve root enhancement indicates lack of integrity of the blood-nerve barrier. In this review, we will present a range of pediatric conditions that can present with spinal nerve root enhancement including inflammatory, infectious, hereditary, and neoplastic causes. Familiarity with the various pathologic entities associated with spinal nerve root enhancement is important for a concise differential diagnosis in the appropriate clinical setting. This will avoid unnecessary additional investigations. [ABSTRACT FROM AUTHOR]

Aim The aim of this study was to explore changes in motor function up to 10 years after selective dorsal rhizotomy (SDR). Method The participants comprised 29 children (20 males, nine females) with bilateral spastic diplegia who were consecutively operated on at a median age of 4 years and 3 months and followed until a median age of 15 years. SDR was combined with physiotherapy and regular follow-up visits. The distribution of preoperative Gross Motor Function Classification System (GMFCS) levels was as follows: I, n=1; II, n=7; III, n=8; IV, n=12; and V, n=1. Muscle tone in hip flexors, hip adductors, knee flexors, and plantar flexors was assessed with the modified Ashworth scale, passive range of motion in hip abduction, popliteal angle, maximum knee extension, dorsiflexion of the foot was measured with a goniometer, and gross motor function was assessed using the Gross Motor Function Measure (GMFM-66). The results were compared with preoperative values, taking into account age at the time of SDR. Results After 10 years, muscle tone in hip flexors, hip adductors, knee flexors and plantar flexors was normalized in 19, 24, 13 and 23 participants respectively; mean change in passive range of motion ranged from −2.0° to 8.6°, and the mean increase in GMFM-66 was 10.6. Changes in GMFM-66 were associated with preoperative GMFCS level and GMFM-66 scores. Interpretation Children who underwent SDR and physiotherapy and were regularly followed up by an experienced team showed improved gross motor function for up to 10 years postoperatively. [ABSTRACT FROM AUTHOR]

The article discusses a study that evaluated the long-term effects of selective dorsal rhizotomy (SDR) in pediatric patients with cerebral palsy (CP). The subjects were prospectively assessed at different time periods after SDR. It was found that baseline muscle tone at the knee, hop, and ankle level showed a high degree of spasticity that normalized after SDR. The spasticity-reducing effect of SDR is seen to suggest that contracture development in CP is not mediated only by spasticity.

The article discusses a study that compares function and gait in a group of certain older children who received selective dorsal rhizotomy (SDR) with age- and function-matched children who received either no surgery or orthopedic surgery. Ambulatory children with diplegic cerebral palsy and categorized in levels I or II of the Gross Motor Function Classification System (GMFCS). It was found that the group that received orthopedic surgery showed improved gait compared with the group that did not undergo surgery.

Afferent inputs are known to modulate the activity of locomotor central pattern generators, but their role in the generation of locomotor patterns remains uncertain. This study sought to investigate the importance of afferent input for producing bilateral, coordinated hindlimb stepping in adult cats. Following complete spinal transection, animals were trained to step on the moving belt of a treadmill until proficient, weight-bearing stepping of the hindlimbs was established. Selective dorsal rhizotomies of roots reaching various segments of the lumbosacral enlargement were then conducted, and hindlimb stepping capacity was reassessed. Depending on the deafferented lumbosacral segments, stepping was either abolished or unaffected. Deafferentation of mid-lumbar (L3/L4) or lower-lumbar (L5-S1) segments abolished locomotion. Locomotor capacity in these animals could not be restored with the administration of serotonergic or adrenergic agonists. Deafferentation of L3, L6, or S1 had mild effects on locomotion. This suggested that critical afferent inputs pertaining to hip position (mid-lumbar) and limb loading (lower-lumbar) play an important role in the generation of locomotor patterns after spinal cord injury. [ABSTRACT FROM AUTHOR]

This study retrospectively evaluated the safety and efficacy of selective dorsal rhizotomy (SDR) in participants who underwent a rigorous selection process, uniform surgical procedure, and a standardized postoperative rehabilitation process. Outcome measures assessed were the Ashworth scale for spasticity, the Gillette Gait Index (GGI) for overall gait pathology, oxygen cost for gait efficiency, and the Gillette Functional Assessment Questionnaire (functional walking ability scale; [FAQ]) for functional mobility. Outcomes were evaluated for 136 children (81 males, 55 females; mean age 7y 3mo [SD 2y 1mo], range 3y 5mo–18y 9mo) for an average of 18.3 months (SD 4.4mo) postoperatively. All participants had a diagnosis of cerebral palsy (CP): 10 quadriplegia, 19 triplegia, and 107 diplegia. Preoperative Gross Motor Function Classification System levels were: Level I n=6; Level II n=64; Level III n=59, and Level IV n=7. All outcome measures improved for the group as a whole. Spasticity improved with 66 to 92% of possible gain in Ashworth scores; GGI was 7.5 times more likely to have a good as opposed to a poor outcome; energy efficiency improved in over half of the participants, and the FAQ demonstrated a statistically significant improvement of 0.9 levels ( p<0.001). The rate of complications was low, with peri- and postoperative complications resolved by time of discharge. [ABSTRACT FROM AUTHOR]

Background: Children undergoing selective dorsal rhizotomy (SDR) experience severe pain postoperatively; a pain related to both the extensive surgical exposure with multilevel laminectomy and nerve root manipulation. We sought to define an optimal dose of continuous intrathecal (IT) morphine and bupivacaine to treat this severe pain. The aim of this study was to compare two different concentrations of morphine in a fixed dose of bupivacaine with regard to the analgesic effect and survey if they differed in side effects. Methods: Twenty-six children, aged 2.7–7.4 years undergoing SDR were included in this study. Postoperatively 11 children received a continuous infusion of morphine 0.4 μg.kg−1.h−1 and bupivacaine 40 μg.kg−1.h−1 (low-dose group) and 15, a continuous infusion of morphine 0.6 μg.kg−1.h−1 and bupivacaine 40 μg.kg−1.h−1 (high-dose group). The Behavioral Observational Pain Scale (BOPS) was used to evaluate pain. Results: Better pain relief was obtained in the high-dose group seen in lower BOPS score compared with the low-dose group [ P = 0.03, Fisher's permutation test and P = 0.06 Wilcoxon–Mann–Whitney (WMW) test]. The low-dose group received seven times as much ketobemidone 0.43 ± 0.54 mg.kg−1 48 h−1 compared with 0.06 ± 0.09 mg.kg−1 48 h−1 in the high-dose group ( P = 0.0005 Fisher's permutation test, P = 0.0017 WMW test). There was no statistical difference in pruritus and postoperative nausea and vomiting between the groups. Respiratory and hemodynamic depression was not found. Conclusion: This study shows that, compared with low-dose, the higher dose of continuous IT morphine combined with bupivacaine, significantly reduce pain score and postoperative intravenous analgesic requirements without increasing adverse effects. [ABSTRACT FROM AUTHOR]

Functional recovery after large excision of dorsal roots is absent because of both the limited regeneration capacity of the transected root, and the inability of regenerating sensory fibers to traverse the dorsal root entry zone. In this study, bioresorbable guidance conduits were used to repair 6-mm dorsal root lesion gaps in rats, while neurotrophin-encoding adenoviruses were used to elicit regeneration into the spinal cord. Polyester conduits with or without microfilament bundles were implanted between the transected ends of lumbar dorsal roots. Four weeks later, adenoviruses encoding NGF or GFP were injected into the spinal cord along the entry zone of the damaged dorsal roots. Eight weeks after injury, nerve regeneration was observed through both types of implants, but those containing microfilaments supported more robust regeneration of calcitonin gene-related peptide (CGRP)-positive nociceptive axons. NGF overexpression induced extensive regeneration of CGRP(+) fibers into the spinal cord from implants showing nerve repair. Animals that received conduits containing microfilaments combined with spinal NGF virus injections showed the greatest recovery in nociceptive function, approaching a normal level by 7-8 weeks. This recovery was reversed by recuffing the dorsal root through the centre of the conduit, demonstrating that regeneration through the implant, and not sprouting of intact spinal fibers, restored sensory function. This study demonstrates that a combination of PNS guidance conduits and CNS neurotrophin therapy can promote regeneration and restoration of sensory function after severe dorsal root injury. [ABSTRACT FROM AUTHOR]

The author discusses the article "Functional decline in children undergoing selective dorsal rhizotomy after age 10," by B. A. MacWilliams and colleagues and published within the issue. It focuses on how two similar groups of adolescents with cerebral palsy underwent selective dorsal rhizotomy (SDR) and single event multi-level surgery (SEMLS). The study also discusses how SDR is more likely to be appropriate in early childhood and that it may be generally inappropriate in adolescence when other factors apart from spasticity are more important.

The author discusses the article "Does loss of spasticity matter? A 10-year follow-up after selective dorsal rhizotomy in cerebral palsy," by K. Tedroff and colleagues and published in the issue. The study followed up on 15 patients ten years after they underwent selective dorsal rhizotomy (SDR) and assessed outcome measures such as the Modified Ashworth Scale (MAS), Gross Motor Function Measure 88 (GMFM-88) and the Wilson gait scale. The authors also found that the spasticity-reducing effect of SDR did not seem to improve long-term functioning.