Peripheral nerve repair throughout the body with processed nerve allografts: Results from a large multicenter study.

BACKGROUND: Peripheral nerve damage resulting in pain, loss of sensation, or motor function may necessitate a reconstruction with a bridging material. The RANGER® Registry was designed to evaluate outcomes following nerve repair with processed nerve allograft (Avance® Nerve Graft; Axogen; Alachua, FL). Here we report on the results from the largest peripheral nerve registry to-date. METHODS: This multicenter IRB-approved registry study collected data from patients repaired with processed nerve allograft (PNA). Sites followed their own standard of care for patient treatment and follow-up. Data were assessed for meaningful recovery, defined as ≥S3/M3 to remain consistent with previously published results, and comparisons were made to reference literature. RESULTS: The study included 385 subjects and 624 nerve repairs. Overall, 82% meaningful recovery (MR) was achieved across sensory, mixed, and motor nerve repairs up to gaps of 70 mm. No related adverse events were reported. There were no significant differences in MR across the nerve type, age, time-to-repair, and smoking status subgroups in the upper extremity (p > .05). Significant differences were noted by the mechanism of injury subgroups between complex injures (74%) as compared to lacerations (85%) or neuroma resections (94%) (p = .03) and by gap length between the <15 mm and 50-70 mm gap subgroups, 91 and 69% MR, respectively (p = .01). Results were comparable to historical literature for nerve autograft and exceed that of conduit. CONCLUSIONS: These findings provide clinical evidence to support the continued use of PNA up to 70 mm in sensory, mixed and motor nerve repair throughout the body and across a broad patient population.

Common radiographic imaging modalities fail to accurately predict capitate morphology.

BACKGROUND: There are three morphologies of the capitate based on its lunate and scaphoid articulations: flat, spherical, and V-shaped. Following a proximal row carpectomy (PRC), the capitate articulates with the lunate facet of the radius, altering contact biomechanics at the radiocarpal joint. Therefore, capitate morphology may influence contact pressures at the capitolunate articulation and influence clinical outcomes after PRC. However, it remains unclear which diagnostic imaging technique most reliably distinguishes between capitate morphologies. METHODS: We evaluated the ability of plain radiographs, two-dimensional computed tomography (2D-CT), three-dimensional (3D)-CT reconstruction, and magnetic resonance imaging (MRI) to predict capitate type in 47 fresh frozen cadaver wrists. Two attending hand surgeons and one hand surgery fellow characterized capitate type based on each imaging modality. True capitate type was determined after gross dissection. We determined the reliability of each modality to predict capitate morphology. RESULTS: We found all four imaging modalities to have a low sensitivity and specificity for predicting capitate morphology. Plain radiographs, 2D-CT, 3D-CT, and MRI had sensitivities/specificities of 0.46/0.57, 0.54/0.72, 0.54/0.52, and 0.56/0.65, respectively. All modalities had high negative predictive values for detecting the more rare V-shaped capitate subtype (range 91-94 %). Inter-rater reliability was poor for all modalities. CONCLUSION: These data suggest that plain radiographs, CT, 3D-CT, and MRI are not helpful in preoperative determination of true capitate morphology. Plain radiographs are as effective as more cost-intensive modalities in ruling out V-shaped capitates.

Midcarpal Instability: A Comprehensive Review and Update.

Midcarpal instability has been well described as a clinical entity but the pathokinematics and pathologic anatomy continue to be poorly understood. This article presents a comprehensive review of the existing knowledge and literature-based evidence for the diagnosis and management of the various entities comprising midcarpal instability. It discusses the limitations of the current understanding of midcarpal instability and proposes new directions for furthering knowledge of the causes and treatment of midcarpal instability and wrist pathomechanics in general.

Surgical Techniques for the Management of Midcarpal Instability.

Palmar midcarpal instability (PMCI) is an uncommon and poorly understood disorder. Its etiology is believed to be due to traumatic or congenital laxity of the ligaments (volar and dorsal) that stabilize the proximal row. This laxity results in hypermobility of the proximal carpal row and unphysiologic coupling of the midcarpal joint. Clinically, the condition is manifested by a painful clunk with ulnar and radial wrist deviation. The purpose of this article is to chronicle our personal experience with this condition and to review our current treatment recommendations and outcomes.

Posttraumatic stress symptoms in children recovering from minor orthopaedic injury and treatment.

BACKGROUND: This study was designed to determine the prevalence of high levels of posttraumatic stress disorder (PTSD) symptoms among pediatric orthopaedic trauma patients recovering from injury and to see whether injury or demographic variables are associated with the presence of the symptoms. METHODS: Four hundred pediatric orthopaedic trauma patients completed the Child PTSD Symptom Scale questionnaire. Demographic and injury variables were tested to see if any were associated with the presence of high levels of posttraumatic stress symptoms. RESULTS: The average age of respondents was 11 years. The average time since injury was 36 days. The mean Injury Severity Score and summed Extremity Abbreviated Injury Score were 4 and 2, respectively. A total of 130 (33%) met criteria for high levels of PTSD symptoms. None of the variables tested were associated with high levels of PTSD symptoms, except one. Patients admitted to the hospital after injury were significantly more likely to develop high levels of PTSD symptoms. CONCLUSIONS: High levels of posttraumatic stress disorder symptoms are common in the recovery period after pediatric orthopaedic trauma, even among patients with relatively minor injury. Children admitted to the hospital after injury are at higher risk for such symptoms.

LIM homeobox gene-dependent expression of biogenic amine receptors in restricted regions of the C. elegans nervous system.

Biogenic amines regulate a variety of behaviors. Their functions are predominantly mediated through G-protein-coupled 7-transmembrane domain receptors (GPCR), 16 of which are predicted to exist in the genome sequence of the nematode Caenorhabditis elegans. We describe here the expression pattern of several of these aminergic receptors, including two serotonin receptors (ser-1 and ser-4), one tyramine receptor (ser-2), and two dopamine receptors (dop-1 and dop-2). Moreover, we describe distinct but partially overlapping expression patterns of different splice forms of the ser-2 tyramine receptor locus. We find that each of the aminergic receptor genes is expressed in restricted regions of the nervous system and that many of them reveal significant overlap with the expression of regulatory factors of the LIM homeobox (Lhx) gene family. We demonstrate that the expression of several of the biogenic amine receptors is abrogated in specific cell types in Lhx gene mutants, thus establishing a role for these Lhx genes in regulating aspects of neurotransmission. We extend these findings with other cell fate markers and show that the lim-4 Lhx gene is required for several but not all aspects of RID motor neuron differentiation and that the lim-6 Lhx gene is required for specific aspects of RIS interneuron differentiation. We also use aminergic receptor gfp reporter fusions as tools to visualize the anatomy of specific neurons in Lhx mutant backgrounds and find that the development of the elaborate dendritic branching pattern of the PVD harsh touch sensory neuron requires the mec-3 Lhx gene. Lastly, we analyze a mutant allele of the ser-2 tyramine receptor, a target of the ttx-3 Lhx gene in the AIY interneuron class. ser-2 mutants display none of the defects previously shown to be associated with loss of AIY function.

Serotonin regulates repolarization of the C. elegans pharyngeal muscle.

Caenorhabditis elegans feeds by rhythmically contracting its pharynx to ingest bacteria. The rate of pharyngeal contraction is increased by serotonin and suppressed by octopamine. Using an electrophysiological assay, we show that serotonin and octopamine regulate two additional aspects of pharyngeal behavior. Serotonin decreases the duration of the pharyngeal action potential and enhances activity of the pharyngeal M3 motor neurons. Gramine, a competitive serotonin antagonist, and octopamine have effects opposite to those of serotonin: gramine and octopamine increase action potential duration and suppress M3 activity. The effects of serotonin, gramine and octopamine on action potential duration are dependent on the pharyngeal motor neurons MC and M3. When the MC and M3 motor neurons are functionally defective, serotonin and octopamine do not regulate the action potential. Our data suggest that serotonin alters pharyngeal physiology to allow for rapid contraction-relaxation cycles. Reciprocal regulation of pharyngeal behavior by serotonin and octopamine provides a mechanism for adapting to the presence and absence of food, respectively.