Laura G. Hamant, P. David Adelson, Paul Kang, S. Danielle Brown, and Jorge I. Arango
The goal of this study was to determine the functional efficacy of acellular processed nerve allograft (ALG) as compared to sural nerve autograft (AUG) harvested at time of surgery for children with obstetrical brachial plexus injury (OBPI).
A retrospective review of records was performed in patients who underwent surgical repair of OBPI between 2009 and 2015 at Phoenix Children’s Hospital. Patients were grouped based on the type of nerve graft used (AUG using the patient’s own sural nerve or decellularized processed cadaveric nerve ALG) and compared in terms of motor strength, British Medical Research Council score, functionality (Mallet scale score), surgical time, rate of complications, and need for further intervention.
A total of 52 records were identified meeting study criteria. Sural nerve AUG was used in 22 cases and ALG in 30 cases. Changes from pre- to postsurgical assessment of motor strength were significant for all muscle groups measured except for elbow extension for both groups. All Mallet scores increased significantly. No significant differences were observed in motor strength and functional components between groups. Interventions using ALG had shorter operative times than those performed using AUG. No significant difference was observed in terms of need for further intervention. Two patients (9%) in the AUG group developed stitch abscesses at the harvest site, whereas there were no infectious complications reported in the ALG group.
These findings suggest equivalence in terms of muscle strength and functional outcomes between the use of AUG and ALG for patients with OBPI. However, the less invasive character of ALG repair decreases surgical time and risk of complications.
Martina Stippler, Veronica Ortiz, P. David Adelson, Yue-Fang Chang, Elizabeth C. Tyler-Kabara, Stephen R. Wisniewski, Ericka L. Fink, Patrick M. Kochanek, S. Danielle Brown, and Michael J. Bell
Minimizing secondary brain injuries after traumatic brain injury (TBI) in children is critical to maximizing neurological outcome. Brain tissue oxygenation monitoring (as measured by interstitial partial pressure of O2 [PbO2]) is a new tool that may aid in guiding therapies, yet experience in children is limited. This study aims to describe the authors' experience of PbO2 monitoring after TBI. It was hypothesized that PbO2 thresholds could be established that were associated with favorable neurological outcome, and it was determined whether any relationships between PbO2 and other important clinical variables existed.
Forty-six children with severe TBI (Glasgow Coma Scale score ≤ 8 after resuscitation) who underwent PbO2 and brain temperature monitoring between September 2004 and June 2008 were studied. All patients received standard neurocritical care, and 24 were concurrently enrolled in a trial of therapeutic early hypothermia (n = 12/group). The PbO2 was measured in the uninjured frontal cortex. Hourly recordings and calculated daily means of various variables including PbO2, intracranial pressure (ICP), cerebral perfusion pressure (CPP), mean arterial blood pressure, partial pressure of arterial O2, and fraction of inspired O2 were compared using several statistical approaches. Glasgow Outcome Scale scores were determined at 6 months after injury.
The mean patient age was 9.4 years (range 0.1–16.5 years; 13 girls) and 8554 hours of monitoring were analyzed (PbO2 range 0.0–97.2 mm Hg). A PbO2 of 30 mm Hg was associated with the highest sensitivity/specificity for favorable neurological outcome at 6 months after TBI, yet CPP was the only factor that was independently associated with favorable outcome. Surprisingly, instances of preserved PbO2 with altered ICP and CPP were observed in some children with unfavorable outcomes.
Monitoring of PbO2 demonstrated complex interactions with clinical variables reflecting intracranial dynamics using this protocol. A higher threshold than reported in studies in adults was suggested as a potential therapeutic target, but this threshold was not associated with improved outcomes. Additional studies to assess the utility of PbO2 monitoring after TBI in children are needed.
Ekta Tiwari, Danielle M. Salvadeo, Alan S. Braverman, Nagat A. Frara, Lucas Hobson, Geneva Cruz, Justin M. Brown, Michael Mazzei, Michel A. Pontari, Amanda R. White, Mary F. Barbe, and Michael R. Ruggieri Sr.
Previous patient surveys have shown that patients with spinal cord or cauda equina injuries prioritize recovery of bladder function. The authors sought to determine if nerve transfer after long-term decentralization restores bladder and sphincter function in canines.
Twenty-four female canines were included in this study. Transection of sacral roots and hypogastric nerves (S Dec) was performed in 6 animals, and 7 animals underwent this procedure with additional transection of the L7 dorsal roots (L7d+S Dec). Twelve months later, 3 L7d+S Dec animals underwent obturator-to-pelvic nerve and sciatic-to-pudendal nerve transfers (L7d+S Dec+Reinn). Eleven animals served as controls. Squat-and-void behaviors were tracked before and after decentralization, after reinnervation, and following awake bladder-filling procedures. Bladders were cystoscopically injected with Fluoro-Gold 3 weeks before euthanasia. Immediately before euthanasia, transferred nerves were stimulated to evaluate motor function. Dorsal root ganglia were assessed for retrogradely labeled neurons.
Transection of only sacral roots failed to reduce squat-and-void postures; L7 dorsal root transection was necessary for significant reduction. Three L7d+S Dec animals showing loss of squat-and-void postures post-decentralization were chosen for reinnervation and recovered these postures 4–6 months after reinnervation. Each showed obturator nerve stimulation–induced bladder contractions and sciatic nerve stimulation–induced anal sphincter contractions immediately prior to euthanasia. One showed sciatic nerve stimulation–induced external urethral sphincter contractions and voluntarily voided twice following nonanesthetized bladder filling. Reinnervation was confirmed by increased labeled cells in L2 and the L4–6 dorsal root ganglia (source of obturator nerve in canines) of L7d+S Dec+Reinn animals, compared with controls.
New neuronal pathways created by nerve transfer can restore bladder sensation and motor function in lower motor neuron–lesioned canines even 12 months after decentralization.