Validation of the Subjective Spine Value: A new single item score for the assessment of spine-specific function.

BACKGROUND: Spinal function can be assessed through different patient reported outcome measures (PROMs). PURPOSE: The aim of the present study was to evaluate a novel single-item score for the assessment of spinal function: The Subjective Spine Value (SSpV). It was hypothesized that the SSpV correlates with the established scores Oswestry disability index (ODI) and Core Outcome Measures Index (COMI). METHODS: Between 08/2020 and 11/2021 151 consecutive patients were prospectively enrolled and completed a questionnaire with the ODI, COMI as well as the SSpV. Patients were divided into 4 groups depending on their specific pathology (Group 1: Degenerative pathologies, Group 2: Tumor, Group 3: Inflammatory / Infection, Group 4: Trauma). Pearson correlation coefficient was used to evaluate correlation between the SSpV and the ODI and COMI separately. Floor and ceiling effects were evaluated. RESULTS: Overall, the SSpV correlated significantly with both ODI (p = < 0.001; r = - 0.640) and COMI (p = < 0.001; r = - 0.640). This was also observed across all investigated groups (range - 0.420-0.736). No relevant floor or ceiling effects were noticed. CONCLUSIONS: The SSpV is a valid single-item score for the assessment of spinal function. The SSpV offers a useful tool to efficiently assess spinal function in a variety of spinal pathologies. LEVEL OF EVIDENCE: I, prospective cohort study.

The role of CT scan in postoperative evaluation of distal radius fractures: Retrospective analysis in regard to complications and revision rates.

BACKGROUND: Intraarticular fractures of the distal radius present a challenging problem for surgeons. While preoperative CT scans are considered helpful to understand the type of fracture and to choose an adequate approach, the role of postoperative CT scans is not yet clearly defined. The aim of this study was to analyze indications for postoperative CT scans and to evaluate its potential therapeutic consequence in regard to detection of complications and its influence on revision rates in intraarticular fractures. These findings were used to establish an algorithm to help identifying patients that benefit from a postoperative CT scan. PATIENTS AND METHODS: Ninety-two patients with intraarticular fractures were included. AO type C fractures were seen in about 90% of patients, with type C3 being present in 55% of the patients. According to Frykman's classification type 7 and 8 fractures were found in 93%. Data was analyzed in regard to radiographic results, complications and indication for a postoperative CT scan. RESULTS: Six patients underwent revision surgery. When analyzing data in regard to correlation of radiographs and CT Scans a statistically significant correlation was found. CONCLUSIONS: A high correlation between both imaging techniques can be shown. In inconclusive radiographs, CT scans are recommended to rule out intraarticular screw placement or step offs. Due to the number of patients and the retrospective design, further studies are needed.

ALIF and total disc replacement versus 2-level circumferential fusion with TLIF: a prospective, randomized, clinical and radiological trial.

STUDY DESIGN: Prospective, randomized trial. PURPOSE: The treatment of degenerative disc disease (DDD) with two-level fusion has been associated with a reasonable rate of complications. The aim of the present study was to compare (Hybrid) stand-alone anterior lumbar interbody fusion (ALIF) at L5/S1 with total disc replacement at L4/5 (TDR) as an alternative surgical strategy to (Fusion) 2-level circumferential fusion employing transforaminal lumbar interbody fusion (TLIF) with transpedicular stabilization at L4-S1. METHODS: A total of 62 patients with symptomatic DDD of segments L5/S1 (Modic ≥2°) and L4/5 (Modic ≤2°; positive discography) were enrolled; 31 were treated with Hybrid and 31 with Fusion. Preoperatively, at 0, 12, and a mean follow-up of 37 months, clinical (ODI, VAS) and radiological evaluations (plain/extension-flexion radiographs evaluated for implant failure, fusion, global and segmental lordosis, and ROM) were performed. RESULTS: In 26 of 31 Hybrid and 24 of 31 Fusion patients available at the final follow-up, we found a significant clinical improvement compared to preoperatively. Hybrid patients had significantly lower VAS scores immediately postoperatively and at follow-up compared to Fusion patients. The complication rates were low and similar between the groups. Lumbar lordosis increased in both groups. The increase was mainly located at L4-S1 in the Hybrid group and at L1-L4 in the Fusion group. Hybrid patients presented with increased ROM at L4/5 and L3/4, and Fusion patients presented with increased ROM at L3/4, with significantly greater ROM at L3/4 compared to Hybrid patients at follow-up. CONCLUSIONS: Hybrid surgery is a viable surgical alternative for the presented indication. Approach-related inferior trauma and the balanced restoration of lumbar lordosis resulted in superior clinical outcomes compared to two-level circumferential fusion with TLIF.

Pelvic tilt compensates for increased acetabular anteversion.

PURPOSE: Pelvic tilt determines functional orientation of the acetabulum. In this study, we investigated the interaction of pelvic tilt and functional acetabular anteversion (AA) in supine position. METHODS: Pelvic tilt and AA of 138 individuals were measured by computed tomography (CT). AA was calculated in relation to the anterior pelvic plane (APP) and relative to the table plane. We analysed these parameters for gender-specific and age-related differences. RESULTS: The mean pelvic tilt was -0.1 ± 5.5°. Pelvic sagittal rotation displayed no gender nor age related differences. Females showed higher angles of AA compared with males (20.0° vs 17.2°, p < 0.001; AA relative to the APP). Anterior tilting of the pelvis positively correlated with AA and individuals with high AA had a higher anterior pelvic tilt compared with those with low AA (p < 0.0001; AA relative to the APP). CONCLUSIONS: AA has to be calculated regarding pelvic sagittal rotation for correct acetabular orientation. Pelvic tilt is dependent on acetabular orientation and compensates for increased AA.

A locking contoured plate for distal fibular fractures: mechanical evaluation in an osteoporotic bone model using screws of different length.

Osteoporotic bone with poor mechanical capacity provides limited stability after fixation of ankle fractures. Stabilization with an implant providing increased fixation strength in osteoporotic bone could reduce failure rates of fixation and allow a more functional treatment. The purpose of this study was to evaluate a locking contoured plate for fixation of distal fibular fractures in comparison with a conventional contoured plate in an osteoporotic bone model. Eighty cylinders of osteoporotic bone surrogates were fixed with the two plates. We performed torque-to-failure and cyclic testing experiments using screws of different length with a Zwick/Roell testing machine. The locking system showed higher torque-to-failure and maximum torque levels as compared with the conventional plate in torque-to-failure experiments and torsional cyclic testing. The locking contoured plate provides improved fixation strength in the osteoporotic bone model. The locking system may be appropriate for fixation of distal fibular fractures, especially in osteoporotic bone with poor mechanical capacity.

Subfascial directionality of perforators of the distal lower extremity: an anatomic study regarding selection of perforators for 180-degree propeller flaps.

BACKGROUND: The 180-degree propeller flaps allow closure of soft-tissue defects of the distal lower extremity. In addition to twist, the pedicle is often subject to additional kinking which increases proportionally to the angle at which the perforator pierces through the fascia. This study evaluates the directionality of the perforators at the fascial level to guide in the selection process of the best perforator. MATERIAL AND METHODS: Perforators were identified in the lower extremities of 16 fresh cadavers. The angle of fascial perforation was measured. Perforators were grouped according to source vessel and location. Results were analyzed statistically regarding angle of fascial perforation along the source vessel and region. RESULTS: A total of 324 perforators were identified. Distal perforators pierced the fascia at a significantly greater angle than in the proximal and middle segment of the peroneal and anterior tibial vessels (P < 0.005). Perforators originating from the posterior tibial artery pierced the fascia at less acute angles distally. When grouped according to the region of the perforators, no significant difference was found between perforators from all source vessels in the proximal region of the distal lower extremity. Even distally, perforators from the posterior tibial artery traveled almost perpendicular (P < 0.005). CONCLUSION: Perforators traveling in a near perpendicular manner are ideal to serve as a pedicle for 180-degree propeller flaps as solely the twist has to be distributed along the vessel. The posterior tibial artery was the source to perforators with the most constant, near-perpendicular course, predisposing them for use in 180-degree propeller flaps.

RNA editing of Kv1.1 channels may account for reduced ictogenic potential of 4-aminopyridine in chronic epileptic rats.

In rat brain slices, the Kv channel blocker 4-aminopyridine (4-AP) induces seizure-like events. This effect is absent in slices from chronic epileptic rats generated using the kainic acid model. The reason for this phenomenon remained elusive as an altered expression level of Kv channels was ruled out as a mechanism. We recently described that the Ile400Val RNA editing of Kv1.1 generates 4-AP-insensitive Kv1 channels (Kv1.1(I400V)). We therefore hypothesized that altered RNA editing levels account for the reduced ictogenic potency of 4-AP in chronic epileptic rats. We found fourfold increased RNA editing ratios in the entorhinal cortex of chronic epileptic animals compared to healthy control animals. Electrophysiologic recordings in Xenopus oocytes revealed that the observed increased Kv1.1(I400V) editing level can in fact lead to significant loss of 4-AP sensitivity. Our data suggest that altered Kv1.1(I400V) RNA editing contributes to the reduced ictogenic potential of 4-AP in chronic epileptic rats.

Biomechanical evaluation of flexor tendon repair using barbed suture material: a comparative ex vivo study.

PURPOSE: Barbed suture material for tendon repair opens up the possibility of a knotless reconstruction due to an increased suture-tendon interaction. The aim of this study was to compare the tensile strength of a knotted technique with a monofilament polydioxane suture to that of a knotless technique with a barbed suture material, by using a multistrand, modified Kirchmayr-Kessler tenorrhaphy. METHODS: Sixty human flexor digitorum tendons were randomized into 4 groups. A modified, knotted, multistrand Kirchmayr-Kessler technique with an absorbable, monofilament polydioxane suture was compared with a modified, knotless, multistrand Kirchmayr-Kessler technique with an absorbable, unidirectional barbed glycolic-carbonate suture. Tendons were distracted to failure. Mode of failure and load to failure were recorded. RESULTS: The knotless 2-strand Kirchmayr-Kessler barbed suture shows a significantly lower tensile strength than the knotted 2-strand polydioxane suture (p < .001). The comparison of the maximum tensile strength of the knotless (glycolic-carbonate) technique with that of the knotted (polydioxane) 4-strand technique resulted in no significant difference in either technique utilized (p = .737). The tensile strength of the 4-strand technique was greater than that of the corresponding 2-strand technique (p < .001). CONCLUSIONS: The 2-strand Kirchmayr-Kessler barbed suture proved to be insufficient and significantly weaker than the 2-strand polydioxane suture, and therefore it cannot be recommended. With the knotless 4-strand Kirchmayr-Kessler technique, the barbed suture material has the potential to be used in flexor tendon surgery, but it has no advantage over the 4-strand polydioxane suture.

Glutamine induces epileptiform discharges in superficial layers of the medial entorhinal cortex from pilocarpine-treated chronic epileptic rats in vitro.

PURPOSE: Glutamine (GLN) is a precursor for synthesis of glutamate and gamma-aminobutyric acid (GABA) and has been found in the cerebrospinal fluid (CSF) at mean concentrations of 0.6 mM. Experiments on slices are usually performed in artificial CSF (aCSF) kept free of amino acids. Therefore, the role of glutamine, particularly in tissue of epileptic animals, remains elusive. METHODS: Using extracellular recordings we studied effects of GLN on field potentials and stimulus-evoked field responses in the medial entorhinal cortex (MEC) of combined entorhinal cortex hippocampal slices from pilocarpine-treated chronic epileptic rats and age-matched saline-injected control rats. RESULTS: In presence of GLN (0.5 and 2 mM) recurrent epileptiform discharges (REDs) were observed in slices from epileptic rats (64% and 80%, respectively), but not in slices from control rats. REDs were restricted to the superficial MEC, suppressed by the alpha-Amino-3-hydroxy-5-methyl-4-isoxazol-propionate (AMPA)/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (30 microM), attenuated by the inhibitor of neuronal glutamine transporters methylamino-isobutyric acid (10 mM), and apparently augmented and prolonged by the GABA(A) receptor antagonist bicuculline-methiodide (5 microM). In contrast, amplitudes of stimulus evoked nonsynaptic and synaptic field responses increased in slices from control rats (+23% and +12% of the reference values) and insignificantly less or not in those of epileptic rats (+6.5% and -0.25%, respectively). Notably, stimulus-evoked slow negative transients confined to slices of epileptic animals were reduced in amplitude (-18%). DISCUSSION: In combined entorhinal hippocampal slices from chronic epileptic animals, GLN induces glutamatergic REDs via neuronal uptake in superficial layers of the MEC where inhibitory function seemed to be partially preserved.

Association Between Lumbar Spinal Degeneration and Anatomic Pelvic Parameters.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The objective was to prove the association between anatomic pelvis parameters and specific types of lumbar spinal degeneration. SUMMARY OF BACKGROUND DATA: Different spinopelvic sagittal profile types are suggested to be associated with specific degenerative lumbar spine pathologies. Because pelvic morphology plays a key role defining the spinal shape as well as its load and function it thereby potentially predisposes the development of spinal degeneration. MATERIALS AND METHODS: Patients with symptomatic lumbar spinal degeneration who were surgically treated in 2 spine departments from March 2011 until August 2016 were included in this retrospective analysis. Single-level degenerative pathologies were classified as lumbar disc herniation (LDH), degenerative disc disease (DDD), lumbar spinal stenosis (LSS), and degenerative spondylolisthesis (DSPL). The constant anatomic pelvic parameters pelvic incidence (PI), pelvic radius (PR), and sacral table angle (STA) were assessed in lateral radiographs of the lumbar spine and compared between the pathologies. RESULTS: In total, 249 patients were assigned to the LDH (n=73), DDD (n=67), LSS (n=42), and DSPL (n=67) groups. Group comparisons revealed significant differences in the anatomic pelvic parameters PR (LDH, 139.5±10.8 mm; DDD, 135.9±14.0 mm; LSS, 127.8±14.3 mm; DSPL, 135.8±12.7 mm; P<0.001), PI (LDH, 53.1±10.0 degrees; DDD, 50.0±9.9 degrees; LSS, 54.5±9.6 degrees; DSPL, 57.1±10.8 degrees; P=0.001), and STA (LDH, 95.3±12.7 degrees; DDD, 105.4±9.0 degrees; LSS, 105.9±11.5 degrees; DSPL, 98.6±9.5 degrees; P<0.001). Post hoc tests indicated significant differences between the PR of the LSS group and that of all other subgroups (P<0.012), the PI of the DDD group and that of DSPL (P<0.001), and the STA of the LDH/DSPL groups and that of the LSS/DDD group (P<0.005). CONCLUSIONS: We found all the constant anatomic parameters to be specific for distinct types of degeneration, suggesting pelvis shape is a predisposing factor for their development. LEVEL OF EVIDENCE: Level III.

Influence of pelvic tilt on functional acetabular orientation.

BACKGROUND: Pelvic tilt influences acetabular orientation (AO). Anatomical AO can be measured in relation to the anterior pelvic plane (APP), functional AO can be calculated relative to table's plane. OBJECTIVE: To assess to what extent functional AO is determined by pelvic tilt and if APP and table plane give equal information for correct AO. METHODS: AO was evaluated by computed tomography (CT) scans of 138 patients. Pelvic tilt, anatomical and functional AO were measured, differences between the two reference planes were calculated. RESULTS: Anatomical and functional acetabular anteversion (AA) were found to be different in 21% of individuals with an enhanced extent of pelvic tilt. Functional AA was increased compared to anatomical AA at high posterior pelvic tilt (p < 0.001). Enlarged anterior tilting of the pelvis reduced APP-related AA (p < 0.002). Anatomical AA positively correlated with pelvic tilt, particularly in females (p < 0.01, correlation coefficient = 0.698, R2 = 0.523). CONCLUSIONS: APP and table plane do not provide equal information about AO at enhanced pelvic tilt. Functional orientation of the acetabulum is dependent on pelvic tilt, which itself is influenced by anatomical AA and should therefore be analyzed for precise AO.

Biomechanical Properties of First Dorsal Extensor Compartment Regarding Adequacy as a Bone-Ligament-Bone Graft.

Bone-ligament-bone grafts for reconstruction of the scapholunate ligament are a valuable tool to prevent disease progression to carpal collapse. Locally available grafts do not require an additional donor site. The first extensor compartment was evaluated biomechanically regarding its possible use as an autograft. METHODS: Twelve native fresh-frozen, human cadaver specimens were tested by applying axial tension in a Zwick Roell machine. Load to failure, transplant elongation, and bony avulsion were recorded. The load to failure was quantitated in newtons (N) and the displacement in length (millimeters). Parameters were set at distinct points as start of tension, 1 mm stretch and 1.5 mm dissociation, failure and complete tear, and were evaluated under magnified visual control. Although actual failure occurred at higher tension, functional failure was defined at a stretch of 1.5 mm. RESULTS: Mean load at 1 mm elongation was 44.1 ± 28 N and at 1.5 mm elongation 57.5 ± 42 N. Failure occurred at 111 ± 83.1 N. No avulsion of the bony insertion was observed. Half the transplants failed in the central part of the ligament, while the rest failed near the insertion but not at the insertion itself. Analysis of tension strength displayed a wide range from 3.8 to 83.7 N/mm at a mean of 33.4 ± 28.4 N/mm. CONCLUSIONS: The biomechanical tensile properties of the first dorsal extensor compartment are similar to those of the dorsal part of the scapholunate ligament. A transplant with a larger bone stock and a longer ligament may display an advantage, as insertion is possible in the dorsal, easily accessible part of the carpal bones rather than in the arête-like region adjacent to the insertion of the scapholunate ligament. In this study, 1.5 mm lengthening of the bone-ligament-bone transplant was defined as clinical failure, as such elongation will cause severe gapping and is considered as failure of the transplant.

Reduced ictogenic potential of 4-aminopyridine in the perirhinal and entorhinal cortex of kainate-treated chronic epileptic rats.

We investigated the potential of 4-AP (50-100 microM) to induce seizure-like events (SLEs) in combined entorhinal cortex-hippocampal slices from Sprague Dawley rats which developed spontaneous limbic seizures following kainic acid induced status epilepticus. Slices from control rats (n=8) displayed SLEs in the entorhinal and perirhinal cortex upon application of 50 or 100 microM 4-AP. By contrast, 4-AP failed to induce SLEs in slices from chronic epileptic rats (n=13) except for one slice from one rat. This animal displayed only minor cell loss in layer III of the entorhinal cortex, in contrast to the other epileptic rats for which layer III neuronal loss was extensive. In all slices from epileptic rats, 4-AP induced recurrent epileptiform discharges similar to the interictal activity observed in control rats. Combined application of 4-AP (100 microM) and bicuculline methiodide (30 microM) induced frequent and prolonged recurrent epileptiform discharges in both control and chronic epileptic rats. 4-AP at 50-100 microM likely affects potassium channels containing Kv1.4, Kv1.5, Kv3.1 or Kv3.2 subunits. Real-time PCR revealed no significant downregulation of Kv1.4, Kv1.5, Kv3.1 or Kv3.2 in the subiculum, entorhinal and perirhinal cortex from chronic epileptic rats compared to controls. However, the expression of Kv3.4, responding to 4-AP in mM range, was significantly reduced. Using sub-unit-specific antibodies, the real-time PCR findings were confirmed by immunocytochemistry. We suggest that after chronic epilepsy, reorganization in the entorhinal cortex is accompanied by adaptations in homeostatic plasticity with anticonvulsant consequences.