Spinous Process Research Articles

Differences in Cervical Spine Fractures in Patients Younger or Older Than 65 Years of Age: Implications for the Canadian C-Spine Rule.

There has been a distinction made in the 2001 Canadian C-Spine Rule regarding patients 65 and older and younger than 65 years of age as far as indications for cervical spine CT scanning. We sought to determine if there are differences in the symptoms, mechanisms of injury, fracture locations, and types that are still relevant in 2024. The institutional review board approved this retrospective study of cervical spine CT emergency department results from 2 hospitals in our health system after reviewing 5 years of data in patients experiencing trauma. In addition to the primary variable of age (younger than 65 years and 65 years and older), we looked at injury mechanism, fracture types, sites, symptoms, and operative or medical treatments. Because the demographics of our home site is different from most towns in the United States, we provide race/ethnicity data. Of 21,986 cervical spine CTs, 190/9455 (2.0%) participants 65 years of age and older and 199/12,531 (1.6%) participants younger than 65 years of age had fractures (total, 389/21,986, 1.8%). There were more cases of falls from standing (106, 55.8%) and falls from a height (46, 4.2%) in those 65 years and older and this mechanism was associated with a higher risk of C1 and C2 fractures (52, 27.4%; and 78, 41.1%, respectively). Among the C1 fractures, anterior and posterior arch fractures predominated (37, 19.5%). For C2 fractures, types 2 and 3 odontoid fractures (39, 20.5%; and 12, 6.3%) were more common in the older cohort. Motor vehicle collisions were more common in the younger cohort (89, 44.7%), and they were associated with more C5-C7 fractures (47, 23.6%; 60, 30.2%; and 66, 33.2%, respectively) including the facets (49, 24.6%), spinous processes (31, 15.6%), and transverse processes (52, 26.1%). Overall, the rates of instability, surgical intervention, and asymptomatic fractures were similar in the 2 age groups. Cervical spine fractures appear in about 1.8% of the CT scans performed in a busy emergency department environment. Fractures in the elderly occur more commonly due to falls, are located at C1 and C2, and may involve ligamentous injuries. Younger patients incur trauma more commonly due to motor vehicle collisions, and they are more likely to affect the posterior elements, especially C5-C7. The differences in trends for fractures in the 65 years of age and older and younger than 65 years of age groups have persisted since the Canadian C-Spine Rule 1996-1998 data were collected.

The lumbar artery perforator free flap as an alternative option for breast reconstruction in low BMI patients: analysis of CT Angiography of donor sites across BMI.

In patients with a low body mass index (BMI), the options for autologous breast reconstruction are limited. With the hypothesis that adipose tissue deposition persists in the lumbar region compared to the abdominal wall, this study sought to investigate the lumbar artery perforator (LAP) free flap as an alternative reconstructive option in patients with deficient autologous donor sites consequent to a low BMI. A retrospective cohort analysis was performed, from a prospectively maintained database, of all consecutive DIEP flap breast reconstructions performed in our unit. A randomized selection of 100 patients with low BMI <22, normal BMI 22-24 and high BMI >30 was performed. Patient computerized tomography scans were analyzed to measure abdominal wall and lumbar tissue thickness and to define anatomical landmark relations of the lumbar artery perforator. A statistically significant difference was identified between the ratio of lumbar to abdominal wall thickness between BMI groups, highlighting preservation of the lumbar thickness in patients with low BMI. The mean distance at which the fourth lumbar perforator entered the subcutaneous tissues was 7.7cm lateral to the spinous process (range 6.4 - 9.5cm), with no significant difference between BMI groups, highlighting this consistent anatomical position. This study confirms a greater lumbar to abdominal wall thickness, therefore volume, in low BMI patients, with consistent lumbar perforator anatomy of 6.4 - 9.5cm lateral to the spinous process. The lumbar artery perforator flap should therefore be strongly considered for autologous breast reconstruction in this patients with a low BMI.

Lumbar spine marker placement errors and soft tissue artifact during dynamic flexion/extension and lateral bending in individuals with chronic low back pain

Quantitative in vivo biomechanical assessments are typically performed with optoelectronic motion capture (MoCap) using retroreflective markers attached to skin. This technique inherently contains measurement errors from both marker placement on palpated bony landmarks and skin motion relative to the underlying bone (i.e., soft tissue artifact (STA)). Research on lumbar spine STA is scarce and limited to young, healthy participants in static positions. This study aimed to evaluate static placement errors, lumbar spine STA from MoCap marker clusters (MMC), and linear relationships between STA and patient characteristics. Thirty-nine participants with cLBP performed three trials each of flexion/extension and lateral bending while imaged simultaneously by MoCap (120 Hz) and dynamic biplane radiography DBR (20 Hz). MMCs were placed 29.5 ± 18.0 mm and 27.1 ± 13.4 mm superior to the most prominent aspect of the L1 and L5 spinous process, respectively. L1 relative to L5 STA was larger during flexion/extension (8.6 ± 5.7°) than lateral bending (4.5 ± 2.1°) (p < 0.001). After correcting for marker placement errors, components of the L1 and L5 STA averaged as much as 16.3 mm and 11.4° during flexion/extension, but only 4.0 mm and 4.8° or less during lateral bending. On average, STA for individual L1 and L5 vertebrae increased as participants moved away from the upright neutral position. STA was participant-dependent, however, age and BMI did not model STA well. Given the inaccuracy in marker placement and wide range of patterns of STA, caution is urged when making clinical decisions or when using computational models to estimate spine tissue loading based upon lumbar spine kinematics obtained from skin-mounted markers.

ID: 328468 10kHz Spinal Cord Stimulation Improves Metrics of Spinal Sensory Processing in a Diabetic Rodent Model

ID: 328468 10kHz Spinal Cord Stimulation Improves Metrics of Spinal Sensory Processing in a Diabetic Rodent Model

Inferior-Medial Dry Needling at the Thoracolumbar Junction: A Cadaveric Study.

Dry needling (DN) has emerged as a popular therapeutic intervention for managing musculoskeletal pain. While major adverse events are generally rare, those that have been reported in vulnerable areas such as the spine and thorax can be serious and warrant further investigation regarding safe techniques in and around these areas. The purpose of this study was to reproduce the methods employed by Williams et al.but with an inferior-medial multifidus DN technique to determine if a dry needle can penetrate the ligamentum flavum (LF) and breach the spinal canal at the thoracolumbar junction. Descriptive Cadaveric study. The procedure was performed on a cadaver in the prone position. The needle was advanced under ultrasound guidance to determine if a 0.30 x 40 mm dry needle inserted lateral to the spinous process of T12 and directed inferior-medially could penetrate the LF and enter the spinal canal. A 0.30 x 40 mm dry needle inserted 1.9 cm lateral to the spinous process of T12 was able to traverse the space between the vertebral laminae of T12 and L1, penetrate the LF, and enter the spinal canal with an inferior-medial needle angulation of 33-degrees medial and 18-degrees inferior. The results of this study demonstrate the feasibility of a dry needle entering the spinal canal at the thoracolumbar junction using an inferior-medial technique. These findings support the potential role of ultrasound guidance in the training and clinical practice of DN, especially in regions where safety issues have been documented. Level IV.

Effects of cervical transcutaneous spinal direct current stimulation on spinal excitability

ObjectiveTo investigate the effects of transcutaneous spinal direct current stimulation (tsDCS) on spinal cord excitability using neurophysiological methods. MethodsSpinal cord motoneuron excitability was assessed using various neurophysiological techniques in a sham-controlled randomized experiment, which involved delivering 2 mA tsDCS and testing four different montages. Transcranial magnetic stimulation (TMS), F-waves to supramaximal ulnar nerve stimulation and somatosensory evoked potentials to upper limb nerves stimulation were measured in the participants with the electrode configuration that yielded the greatest effect, for a total of about 18 min. 18 young volunteers were recruited. ResultsAmong the tested ones, the most promising tsDCS montage was the one with the anode placed on the 7th cervical spinous process and the cathode on the glottis. With this configuration, a significant enhancement of motor responses in the hand muscles to TMS of the contralateral hand motor area was observed during tsDCS (p<0.00001), reaching a plateau after 6 min. This facilitation rapidly declined within a few minutes after the tsDCS was stopped. ConclusionResults of the different techniques suggest a possible contribution to facilitatory neuromodulation of the motoneurons at the cervical spine level. SignificanceThe occurrence of enhanced excitability after tsDCS suggests potential application in individuals with partial corticospinal fiber impairment affecting hand motor function.

Anatomical validation of needle placement for cervical paraspinal mapping of the multifidus.

The paraspinal muscles are an important component of electrodiagnostic testing for radiculopathy. In the cervical region, a protocol for cervical paraspinal mapping assumes accurate placement of the electromyography (EMG) needle into the cervical multifidus. However, there is scant information regarding the accuracy of needle placement in that muscle. This study examines the accuracy of this protocol in sampling the intended multifidus muscle of cadavers. An experienced electromyographer directed needles to multifidus at C5, C7, and T2 spinous processes of 19 embalmed cadavers, and injected color dyes. Separately another examiner dissected the cadavers, noting whether the dye was in the correct location and whether its trajectory approached any "danger zones" of nerve, artery, or joint. The dye was in the multifidus muscle 100% of the time and hit the intended bony target in 79%, 73%, and 79% of C5, C7, and T2 insertions. No insertion was found in a danger zone. The results indicate modest accuracy for EMG needle placement as proposed in the clinical protocol. Clinical utility of this method requires more work including the establishment of norms, sensitivities, specificities, and clinical impact.

Heterogeneity of synaptic NMDA receptor responses within individual lamina I pain-processing neurons across sex in rats and humans.

Excitatory glutamatergic NMDA receptors (NMDARs) are key regulators of spinal pain processing, and yet the biophysical properties of NMDARs in dorsal horn nociceptive neurons remain poorly understood. Despite the clinical implications, it is unknown whether the molecular and functional properties of synaptic NMDAR responses are conserved between males and females or translate from rodents to humans. To address these translational gaps, we systematically compared individual and averaged excitatory synaptic responses from lamina I pain-processing neurons of adult Sprague-Dawley rats and human organ donors, including both sexes. By combining patch-clamp recordings of outward miniature excitatory postsynaptic currents with non-biased data analyses, we uncovered a wide range of decay constants of excitatory synaptic events within individual lamina I neurons. Decay constants of synaptic responses were distributed in a continuum from 1-20ms to greater than 1000ms, suggesting that individual lamina I neurons contain AMPA receptor (AMPAR)-only as well as GluN2A-, GluN2B- and GluN2D-NMDAR-dominated synaptic events. This intraneuronal heterogeneity in AMPAR- and NMDAR-mediated decay kinetics was observed across sex and species. However, we discovered an increased relative contribution of GluN2A-dominated NMDAR responses at human lamina I synapses compared with rodent synapses, suggesting a species difference relevant to NMDAR subunit-targeting therapeutic approaches. The conserved heterogeneity in decay rates of excitatory synaptic events within individual lamina I pain-processing neurons may enable synapse-specific forms of plasticity and sensory integration within dorsal horn nociceptive networks. KEY POINTS: Synaptic NMDA receptors (NMDARs) in spinal dorsal horn nociceptive neurons are key regulators of pain processing, but it is unknown whether their functional properties are conserved between males and females or translate from rodents to humans. In this study, we compared individual excitatory synaptic responses from lamina I pain-processing neurons of male and female adult Sprague-Dawley rats and human organ donors. Individual lamina I neurons from male and female rats and humans contain AMPA receptor-only as well as GluN2A, GluN2B- and GluN2D-NMDAR-dominated synaptic events. This may enable synapse-specific forms of plasticity and sensory integration within dorsal horn nociceptive networks. Human lamina I synapses have an increased relative contribution of GluN2A-dominated NMDAR responses compared with rodent synapses. These results uncover a species difference relevant to NMDAR subunit-targeting therapeutic approaches.

The 3-Steps Approach for Lumbar Stenosis with Anatomical Insights, Tailored for Young Spine Surgeons.

Background/Objectives: Lumbar decompression surgery for degenerative lumbar stenosis is an intervention which addresses a degenerative condition affecting many patients. This article presents a meticulous three-phase surgical approach, derived from our clinical experiences and intertwining anatomical insights, offering a nuanced perspective tailored for the educational needs of young spinal surgeons. Methods: Six hundred and eighty-seven patients who underwent lumbar decompression surgery at a single institution were included in the present study. A retrospective analysis of patient demographics and surgical techniques was performed. All surgeries were performed by a consistent surgical team, emphasizing uniformity in approach. The surgical technique involves a meticulous three-phase process comprising exposure and skeletal visualization; microscopic identification and decompression; and undermining of the spinous process base and contralateral decompression. Results: Presenting results from 530 patients, the study examines demographic characteristics, health profiles, operative details, complications, and clinical assessments. The three-phase approach demonstrates low complication rates, absence of recurrences, and improved clinical outcomes, emphasizing its efficacy. Conclusions: The three-phase surgical approach emerges as a valuable educational tool for both novice and seasoned spinal surgeons. Rooted in anatomical insights, the structured methodology not only caters to the educational needs of young surgeons, but also ensures a standardized and safe procedure. The emphasis on tissue preservation and anatomical points aligns with current trends toward minimally invasive techniques, promising enhanced patient outcomes and satisfaction.

Geometric target margin strategy of proton craniospinal irradiation for pediatric medulloblastoma.

In proton craniospinal irradiation (CSI) for skeletally immature pediatric patients, a treatment plan should be developed to ensure that the dose is uniformly delivered to all vertebrae, considering the effects on bone growth balance. The technical (t) clinical target volume (CTV) is conventionally set by manually expanding the CTV from the entire intracranial space and thecal sac, based on the physician's experience. However, there are differences in contouring methods among physicians. Therefore, we aimed to propose a new geometric target margin strategy. Nine pediatric patients with medulloblastoma who underwent proton CSI were enrolled. We measured the following water equivalent lengths for each vertebra in each patient: body surface to the dorsal spinal canal, vertebral limbus, ventral spinal canal and spinous processes. A simulated tCTV (stCTV) was created by assigning geometric margins to the spinal canal using the measurement results such that the vertebral limb and dose distribution coincided with a margin assigned to account for the uncertainty of the proton beam range. The stCTV with a growth factor (correlation between body surface area and age) and tCTV were compared and evaluated. The median values of each index for cervical, thoracic and lumber spine were: the Hausdorff distance, 9.14, 9.84 and 9.77mm; mean distance-to-agreement, 3.26, 2.65 and 2.64mm; Dice coefficient, 0.84, 0.81 and 0.82 and Jaccard coefficient, 0.50, 0.60 and 0.62, respectively. The geometric target margin setting method used in this study was useful for creating an stCTV to ensure consistent and uniform planning.

10 kHz spinal cord stimulation improves metrics of spinal sensory processing in a male STZ rat model of diabetes

To explore why clinical 10 kHz spinal cord stimulation (10 kHz SCS) might improve neurological function in a model of painful diabetic neuropathy (PDN), the short-term behavioral, electrophysiological, and histological effects of 10 kHz SCS were studied using adult male streptozotocin (STZ)-induced diabetic Sprague-Dawley rats. Four testing groups were established: Naïve controls (N = 8), STZ controls (N = 7), STZ+Sham SCS (N = 9), and STZ+10 kHz SCS (N = 11). After intraperitoneal injection (60 mg/kg) of STZ caused the rats to become hyperglycemic, SCS electrodes were implanted in the dorsal epidural space over the L5-L6 spinal segments in the STZ+Sham SCS and STZ+10 kHz SCS groups and were stimulated for 14 days. The von Frey filament paw withdrawal threshold was measured weekly. At termination, animals were anesthetized and the electrophysiologic response of dorsal horn neurons (receptive field size, vibration, radiant warmth) of the ipsilateral foot was measured. Tissue from the plantar paw surface was obtained post-euthanization for intraepidermal nerve fiber density measurements. In comparison to other control groups, while no significant effect of 10 kHz SCS on peripheral intraepidermal nerve fiber density was observed, 10 kHz SCS ‘normalized’ the central neural response to vibration, receptive field, and paw withdrawal threshold, and elevated the neural response to tissue recovery from warm stimuli. These results suggest that short-term, low intensity 10 kHz SCS operates in the spinal cord to ameliorate compromised sensory processing, and may compensate for reduced peripheral sensory functionality from chronic hyperglycemia, thereby treating a broader spectrum of the sensory symptoms in diabetic neuropathy.

Virtual Reality as a Therapeutic Tool in Spinal Cord Injury Rehabilitation: A Comprehensive Evaluation and Systematic Review.

Introduction: The spinal rehabilitation process plays a crucial role in SCI patients' lives, and recent developments in VR have the potential to efficiently engage SCI patients in therapeutic activities and promote neuroplasticity. Objective: The primary objective of this study is to assess a complete review of the extended impacts of VR-assisted training on spine rehabilitation in SCI patients. Methods: This systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) through a single database search in PubMed/Medline between the dates 1 January 2010 and 1 February 2024. MESH terms and keywords were combined in the following search strategy: (Augmented Reality OR VR OR Virtual Reality) AND (Spine OR Spinal) AND Rehabilitation. Included articles were written in English, involved adults with SCI, included an intervention with VR, AR, or any mixed reality system, and assessed changes in outcomes after the intervention. Results: The search produced 257 articles, and 46 of them were allocated for data extraction to evaluate 652 patients. Both when VR training was analyzed and reviewed separately, and when compared to traditional training, the findings exhibited predominantly promising outcomes, reflecting a favorable trend in the study. VR technologies were used in different settings and customizations, and the medium total time of VR training among the studies was 60.46 h per patient. Conclusions: This auspicious outcome of the study further motivates the intervention of VR and AR in the rehabilitation of SCI patients along with ameliorating their overall holistic well-being.

Investigating the Difference Between Thoracic Kyphosis and its Mobility in Community-Dwelling Older Men and Women

Introduction: The amount of thoracic kyphosis and its mobility may be affected by gender in older adults. This study investigates gender differences in thoracic kyphosis and thoracic spine mobility in healthy older adults. Materials and Methods: In this cross-sectional study, 36 participants among which 21 were female and 15 were male with an age range of 65-80 years participated. The amount of thoracic spine kyphosis was measured in a relaxed standing position and the position of maximum correction of thoracic kyphosis using a flexible ruler between the spinous processes of T12 and C7. The difference between the thoracic kyphosis of the relaxed state and the condition of the maximum correction is used to determine the degree of thoracic spine mobility. Finally, men and women were compared in terms of thoracic kyphosis and thoracic spine mobility. The student t-test was employed to compare kyphosis and spinal mobility between men and women, and the paired student t-test was used to compare kyphosis angle in a relaxed posture and maximum kyphosis correction status. Meanwhile, the Pearson test was utilized to evaluate the relationship between variables. Results: Although there was no statistically significant difference in the mean thoracic kyphosis of relaxation (P=0.13) and maximal correction (P=0.18) status of healthy old men and women, there was a significant positive relationship between the rate of kyphosis angle and the amount of mobility of thoracic kyphosis (P=0.003; r=0.48). Conclusion: There is no difference in the degree of kyphosis and thoracic spine mobility in older men and women. In addition, people with more thoracic kyphosis had more spinal mobility.

Association between movement speed and instability catch kinematics and the differences between individuals with and without chronic low back pain

Studies reported the existence of instability catch (IC) during trunk flexion in patients with chronic low back pain (CLBP). However, different movement speeds can cause different neuromuscular demands resulting in altered kinematic patterns. In addition, kinematic characterization corresponding to clinical observation of IC is still limited. Therefore, this study aimed to determine (1) the association between movement speed and kinematic parameters representing IC during trunk flexion and (2) the differences in kinematic parameters between individuals with and without CLBP. Fifteen no low back pain (NoLBP) and 15 CLBP individuals were recruited. Inertial measurement units (IMU) were attached to T3, L1, and S2 spinous processes. Participants performed active trunk flexion while IMU data were simultaneously collected. Total trunk, lumbar, and pelvic mean angular velocity (T_MV, L_MV, and P_MV), as well as number of zero-crossings, peak-to-peak, and area of sudden deceleration and acceleration (Num, P2P, and Area), were derived. Pearson’s correlation tests were used to determine the association between T_MV and L_MV, P_MV, Num, P2P, and Area. An ANCOVA was performed to determine the difference in kinematic parameters between groups using movement speed as a covariate. Significant associations (P < 0.05) were found between movement speed and other kinematic parameters, except for Area. Results showed that L_MV significantly differed from the P_MV (P = 0.002) in the CLBP group, while a significant between-group difference (P = 0.037) was found in the P_MV. Additionally, significant between-group differences (P < 0.05) in P2P and Area were observed. The associations between movement speed and kinematic parameters suggest that movement speed changes can alter kinematic patterns. Therefore, clinicians may challenge lumbopelvic neuromuscular control by modifying movement speed to elicit greater change in kinematic patterns. In addition, the NoLBP group used shared lumbar and pelvic contributions, while the CLBP group used less pelvic contribution. Finally, P2P and Area appeared to offer the greatest sensitivity to differentiate between the groups. Overall, these findings may enhance the understanding of the mechanism underlying IC in CLBP.

The use of intraoperative CT-neuronavigation in Wiltse approach. A technical note.

The paraspinal approach was first introduced in 1968 and later refined by Leon Wiltse to gain access to the lateral interevertebral foraminal region. However, challenges can arise due to unfamiliarity with this approach, unique patient anatomy, or in case of revision surgery, potentially elevating the risk of complications and/or poor outcome. Here we report on two cases in which the intraoperative Oarm CT neuronavigation was used during a Wiltse approach. Under general anesthesia, the spinous process near the surgical level is exposed through a midline incision. The patient's reference anchor is then attached to the exposed spinous process. Intraoperative CT is acquired and transferred to the Stealth Station S8 Surgical Navigation System (Medtronic). The Wiltse approach is now performed through a paramedian incision under neuronavigation guidance and perfectly tailored to the patient's unique anatomy. The first case was a patient harboring a left lumbar intraextraforaminal schwannoma and the second one was a patient with an extraforaminal lumbar disc herniation at the adjacent level of a previous lumbar instrumentation. We were able to easily identify and remove both the lesions minimizing the surgical approach with no complication and optimal clinical outcome. Our cases demonstrate the feasibility of application of intraoperative O-arm CT-neuronavigation to the Wiltse approach. In our opinion, this technique helps in minimizing the surgical approach and rapidly identifying the lesion of interest. Further studies are needed to address the effective utility and advantages of intraoperative CT-neuronavigation in this specific surgical scenario.

Severe Rigid Scoliosis Deformity Correction Using Extended Posterior Release and Instrumentation: A Retrospective Study.

Sever rigid scoliotic deformity (magnitude of the curve >80° and <25% correction on bending film) correction is a great challenge to spine surgeons. Severe scoliosis when untreated or not treated properly, may lead to severe complications due to curve progression. The aim of operative management is to achieve significant correction of sagittal, coronal, and rotational deformity to avoid neurodeficit, maintain sagittal balance, and improve cardiopulmonary function. In this retrospective study, eight patients with severe rigid scoliosis who underwent through single-staged extended posterior release and spinal fusion between March 2022 and November 2023. The surgical procedures were the excision of the posterior ligament and spinous process, laminectomy, excision of ligament flavum, facetectomy, and posterior spinal fusion utilizing pedicle screws, rods, and sub-laminar wires. Patients were evaluated radiologically using posteroanterior and lateral X-rays of the whole spine and computed tomography scans. Demographic data, pre- and post-operative cobbs angle, osteotomized segment, instrumentation segments, blood loss, operation duration, follow-up duration, and complications were recorded. Pre-operative mean cobbs angle was 94.1° (range 83-110°) and post-operative mean cobbs angle was 33.3° (range 28-42°) with 64.6% scoliosis correction. The mean estimated blood loss was 517 mL (range 300-580 mL). The mean operation duration was 272.5 min (210-340 min). Mean spinal fixation fusion segments were 11.1 (range 8-14). No major complications were noted. Our study concluded that extended posterior-only release, facetectomy, and posterior spinal fusion by utilizing pedicle screws and pre-contoured rods significantly corrected severe and rigid scoliosis with a high correction rate and avoid complications of anterior release. Hence, we can achieve remarkable correction in rigid scoliosis using the proper choice of levels, proper implant, and extended posterior release.

Motor point stimulation activates fewer Ia-sensory nerves than peripheral nerve stimulation in human soleus muscle.

Peripheral nerve stimulation (PNS) and motor point stimulation (MPS) are noninvasive techniques used to induce muscle contraction, aiding motor function restoration in individuals with neurological disorders. Understanding sensory inputs from PNS and MPS is crucial for facilitating neuroplasticity and restoring impaired motor function. Although previous studies suggest that MPS could induce Ia-sensory inputs less than PNS, experimental evidence supporting this claim is insufficient. Here, we implemented a conditioning paradigm combining transcutaneous spinal cord stimulation (tSCS) with PNS or MPS to investigate their Ia-sensory inputs. This paradigm induces postactivation depression of spinal reflexes associated with transient decreases in neurotransmitter release from Ia-afferent terminals, allowing us to examine the Ia-sensory input amount from PNS and MPS based on the depression degree. We hypothesized that MPS would induce less postactivation depression than PNS. Thirteen individuals underwent MPS and PNS on the soleus muscle as conditioning stimuli, with tSCS applied to the skin between the spinous processes (L1-L2) as test stimuli. PNS- and MPS-conditioned spinal reflexes were recorded at five interstimulus intervals (ISIs) and four intensities. Results revealed that all PNS conditioning showed significant decreases in spinal reflex amplitudes, indicating postactivation depression. Furthermore, PNS conditioning exhibited greater depression for shorter ISIs and higher conditioning intensities. In contrast, MPS conditioning demonstrated intensity-dependent depression, but without all-conditioning depression and clear ISI dependency as seen in PNS conditioning. In addition, PNS induced significantly greater depression than MPS across most conditions. Our findings provide experimental evidence supporting the conclusion that MPS activates Ia-sensory nerves less than PNS.NEW & NOTEWORTHY Peripheral nerve stimulation (PNS) and motor point stimulation (MPS) induce neuroplasticity, but differences in their effects on Ia-sensory inputs are unclear. We investigated their Ia-sensory inputs using a conditioning paradigm with spinal reflexes. Results showed that PNS conditioning significantly inhibited spinal reflexes than MPS conditioning, indicating greater postactivation depression due to Ia-sensory nerve activation. These findings provide experimental evidence that MPS activates Ia-sensory nerves to a lesser extent than PNS, enhancing our understanding of neuroplasticity.

MORPHOMETRIC CHARACTERISTICS OF NECK PARAMETERS IN THE PERINATAL PERIOD OF ONTOGENESIS

This study aims – to establish the normative morphometric parameters of the neckcircumference, anterior- posterior diameter, height, and width during the perinatal periodof ontogenesis, after which the parameters will be used to construct anatomical models. Material and Methods. The study was conducted on 63 human fetuses aged 4 to10 months and 7 newborns (including 5 isolated organ systems). To create anatomicalmodels, the well-known dimensions of the neck in all age groups were determined usinga centimeter tape and a caliper. The neck circumference was measured at the level of thehyoid bone. The anteroposterior neck diameter was defined as the distance between thebody of the hyoid bone and the VII spinous process of the cervical vertebra. Neck heightwas measured from the upper to the lower neck borders. Neck width was determined inthe frontal plane at the level of the hyoid bone between the lateral edges of the neck.Statistical analysis of the data was performed using the licensed program RStudio.Results. A morphometric analysis of the average values of the well-known neck parameters,namely its circumference, anterior- posterior diameter, height, and width, was conductedin the perinatal period of ontogenesis. The analysis revealed that these parameters exhibitnon-synchronous growth throughout the studied period of the development, with periodsof intensive and relative growth. A correlation analysis was conducted between allmorphometric parameters of the neck of fetuses and newborns. The results demonstratedthat the correlation coefficients between the values of all paired correlation coefficientswere positive and close to 1 (≥0.90), indicating a strong positive correlation between allstudied parameters. A statistical analysis of the data from the Conover- Iman test indicatesthat the median values of the morphometric parameters of the neck cannot be consideredreliable for the pairs «9 months – 10 months» and «10 months – Newborns». This isjustified by the fact that individual anatomical variability is inherent in each individual,and these periods of the development are critical for the neck area. The constructedstandard anatomical models of the morphometric parameters of the neck will serve asa norm for the subsequent determination of certain morphological deviations, which willthen be used to establish variants of the structure and developmental defects of the neck.Conclusions. 1. During the perinatal period of the development, the well-known parametersof the neck, namely its circumference, anterior- posterior diameter, height and width,increase asynchronously. 2. The average values of the morphometric parameters of the neckcircumference and anterior- posterior diameter during the perinatal period of ontogenesisindicate that one period of accelerated development is evident, occurring between the 7thand 9th month of intrauterine development for the neck circumference and between the 6thand 9th month of development for the anterior- posterior diameter of the neck. Two periods ofaccelerated development are observed for the parameters of neck height and width. For neckheight, these periods are from the 5th to the 7th month of development and from the 8th to the9th month of development. For neck width, the periods are from the 4th to the 5th month ofthe development and from the 7th to the 9th month of intrauterine development. In all otherperiods of development, the morphometric parameters of the neck exhibit a slight increase. 3.Based on the arithmetic mean data of the circumference, anterior- posterior diameter, height,and width of the neck, models for predicting the normative morphometric parameters of fetusesand newborns were constructed. The systematized data on the peculiarities of spatial andtemporal transformations of the morphometric parameters of the neck circumference, anteriorposterior diameter, neck height and width, followed by their construction of mathematicalmodels, will contribute to the individualization of the norm, improvement of early diagnosticmethods and development of new methods of surgical correction of congenital neck defects.

Surgical management of congenital cervical spondylolytic spondylolisthesis: illustrative case.

Congenital cervical spondylolytic spondylolisthesis is a rare and complex disorder of the cervical spine. Surgical treatment is reserved for those symptomatic patients who do not improve with conservative management. A 34-year-old man presented with bilateral C7 radiculopathy for the past 6 months. Magnetic resonance imaging of the cervical spine revealed grade II C6-7 spondylolisthesis. Computed tomography showed the presence of spondyloarthritis, bilateral pedicle dysplasia, bilateral isthmic defect, and spinous process schisis. Dynamic radiographs showed no signs of vertebral instability. Dynamic magnetic resonance imaging showed kinking of the spinal cord over the fulcrum of C6-7 kyphosis during flexion, with no signs of myelopathy. The patient underwent C6-7 anterior fusion surgery. His symptoms improved postoperatively, with a 2-month computed tomography scan showing initial bony bridging. The absence of evident instability on radiography does not always correspond to the absence of actual functional compression of neurological structures. Spinal misalignment, muscle dysfunction, and kyphotic deformity with kinking of the spinal cord and stretching of the nerve roots may also contribute to the development of symptoms. In this setting, dynamic magnetic resonance imaging can be extremely useful. Single-level anterior fusion surgery without posterior fixation can achieve solid fusion and improve the clinical conditions of patients. https://thejns.org/doi/10.3171/CASE24174.

Vascularized bone grafts in spinal reconstruction: An updated comprehensive review

In the past two decades, plastic surgeons have advanced to the forefront of spinal surgery, joining orthopedic and neurosurgeons in the multidisciplinary field of spino-plastics. As the global disease burden grows with an increased incidence of spinal pathologies, vascularized bone grafts (VBGs) define the current frontier of spino-plastic surgery. Vascularized bone grafting involves lifting segments of bone with the muscular attachments but without the inclusion of a named vessel. When compared to traditional nonvascular bone grafts and allografts, VBGs have come forward as a favored technique for complex spinal reconstruction due to the unique opportunity to capitalize on the relationship between the tendons and Sharpey's fibers which maintain blood flow to both the bone and muscular segments. This technique ensures robust autologous tissue rearrangement and also takes advantage of the osteoinductive properties of the bone segments, promoting adequate structural support and the perfusion necessary for efficient direct healing and fusion in intricate spine reconstructions. Another one of the many favorable qualities of VBGs is the diversity of sources available to surgeons. The review explores the role of VBGs in enhancing spinal fusion rates and minimizing morbidity compared to traditional approaches. Additionally, a detailed examination of six common VBG sources-the iliac crest, ribs, medial scapula, occiput, spinous processes, and clavicle is included, highlighting each graft's specific techniques and emphasizing the range of options available to spino-plastic surgeons.