Letter: Posterior Vertebral Column Subtraction Osteotomy for Recurrent Tethered Cord Syndrome: A Multicenter, Retrospective Analysis

To the Editor: We read with great interest article by Theodore et al1 entitled “Posterior Vertebral Column Subtraction Osteotomy for Recurrent Tethered Cord Syndrome: A Multicenter, Retrospective Analysis,” recently published in Neurosurgery. The authors elegantly analyzed a multicenter, retrospective cohort of 20 adult patients (mean age 36 yr) recurrent tethered cord syndrome (TCS) which underwent posterior vertebral column subtraction osteotomy (PVCSO). Briefly, this procedure consists removing 90% thoracolumbar vertebra, finally determines spinal column's decrease, to reduce tension on cord. In few words, PVCSO aims imbalance between and length, is condition underlying TCS. All TCS presented were due previous-treated lipomyelomeningoceles (LMMCs); these showed symptoms’ progression less than 2-yr duration. present received at either T12 or L1 fixation 1 level above/below 45% cases; remaining longer fixation. determined, follow-up, relevant improvement resolution leg back pain sensory symptoms, 55% amelioration bowel incontinence, 50% urinary incontinence. Four complications reported: durotomy, wound infection, revision instrumentation failure, onset new deficits. authors’ conclusions underline role technique as definitive treatment symptomatic retethering case failure LMMCs. As pointed al, when complete untethering not achieved during first surgery, risk long-term has been reported, past up, patients; second (or third, fourth, etc) surgery greatly increases rate possible cerebrospinal fluid (CSF) leaks infection neurological deficits; it unclear if procedures carried out intraoperative neurophysiological monitoring not. selected cases, could be therefore feasible solution, despite being major procedure, deserving an expert team. However, we think that key point lipomas meticulous definition what they exactly are. their pivotal paper, Pang al2 defined heterogeneous complex occult dysraphism according moment different embryological stages, describing dorsal, transitional, terminal, chaotic lipomas. They also stated “the literature describes one other lipoma type, lipomyelomeningocele, part distal conus extends alongside fat through dorsal bony defect into extraspinal compartment, dragging small collar fluid. basic structure most commonly transitional but occasionally one.”2 According definition, LMMCs represent mainly extension2,3; such aim should achieve gross-total removal lipomatous tissues, followed surgical “neurulation” neural placode expansile graft duraplasty, obtain very low cord/sac ratio (less 30%). These strategies seem best outcome, redo surgeries, only children population.4 It interesting know, among parameters (mainly ratio) have evaluated, especially amid (8 20) previous only, whether intradural evaluated before proposing osteotomy. group, after achieving total/near-total resection, al reported 2.5% complications, CSF leak obese adults prolonged immobilization. On contrary, considering short follow-up patients’ cohort, stated, effects spine destabilization, pseudarthrosis, adjacent segment disease are unclear. Nevertheless, agree “patients subacute, earlier, stage would potentially benefit more from those chronic recurrence (>2 yr),” about outcome. Also view, that, complexity spectrum diseases, presurgical evaluation comprise standardized assessments urodynamic studies, choose exact time surgery.5 Moreover, many rapidly progressing deteriorations occurrence syringomyelia, block needs adhesiolysis.6 conclusion, considered one-shot whereas can determine favorable outcome incomplete performed subsequent operation. praised results, demonstrating successful multiple surgeries (7 3 untethering, up 17 times), adding contribution neurosurgical armamentarium challenging disease. Funding This study did receive any funding financial support. Disclosures no personal, financial, institutional drugs, materials, devices described article.