Total resection of presacral giant schwannoma via minimally invasive dorsal approach: illustrative case

BACKGROUND Giant presacral schwannomas are extremely rare in neurosurgery. There are various approaches to the surgical treatment of symptomatic giant presacral schwannomas. The least traumatic is the one-stage surgery with a dorsal approach. OBSERVATIONS The authors describe a case of a 52-year-old male with pain in the sacral region and partial urinary dysfunction. A total tumor resection through a minimally invasive dorsal approach was performed, and anatomical and functional preservation of all sacral nerves with no postoperative complications was achieved. LESSONS The authors have shown the possibility of total tumor resection with a minimally invasive dorsal approach without the development of intra- and postoperative complications. Operative corridors that have been created by a tumor can be used and expanded for a minimally invasive dorsal approach to facilitate resection and minimize tissue disruption.

Anatomical study of the innervation of different parts of the posterior ligamentous region of the sacroiliac joint

Background and objectivesThe periarticular sacroiliac joint (SIJ) technique has become an important area of focus, and the quartering of the SIJ posterior ligamentous region has been proposed as a way to refine this technique. However, detailed nerve distribution combined with the division of the SIJ posterior ligamentous region is lacking. We aimed to explore the innervation of the SIJ posteriorly based on the quartering of the SIJ posterior ligamentous region.MethodsSixteen SIJs from eight embalmed cadavers were studied. Each SIJ posterior ligamentous region was equally divided into areas 0–3 from top to bottom. The origin, distribution, quantity, transverse diameter, spatial orientation, relation with bony structures, and the number of identifiable terminal nerve branches in each area were examined.ResultsAreas 0–1 were innervated by the lateral branches of the dorsal rami of L4−L5 directly in all specimens. Areas 2–3 were innervated by that of both lumbar and sacral nerves via the posterior sacral network (PSN), with L5 contributing to the PSN in all specimens and L4 in 68.75%. The number of identifiable terminal nerve branches were significantly higher in areas 2–3 than in areas 0–1.ConclusionsThe inferior part of the SIJ posterior ligamentous region seems to be the main source of SIJ-related pain and is innervated by lumbar and sacral nerves via the PSN. However, the superior part directly innervated by lumbar nerves should not be neglected, and further clinical verification is needed.

Sacral neuromodulation system for treating refractory overactive bladder

Sacral neuromodulation (SNM) is a therapy system used to improve bladder function, including in people with overactive bladder (OAB). It is safe and can improve quality of life. SNM helps improve symptoms through direct modulation of nerve activity; it involves electrically stimulating the sacral nerves that carry signals between the pelvic floor, spinal cord and the brain and is thought to normalise neural communication between the bladder and brain. If patients with OAB do not respond to non-surgical and conservative options, minimally invasive procedures can be offered, including SNM. SNM is performed in two stages: the trial phase, to assess whether it would be effective in the long term; and permanent implantation. This year, the National Institute for Health and Care Excellence (NICE) released guidance on the Axonics SNM System® for treating refractory OAB. The Axonics System is rechargeable and lasts at least 15 years, minimising the need for repeat surgery. NICE suggests the Axonics System may have cost advantages for the NHS. Having more than one SNM therapy option available increases options for patients, offering them a choice of handsets and rechargeable versus non-rechargeable implants. Three case studies illustrate how the system works in practice.

The lumbosacral plexus of the red-rumped agouti (Dasyprocta leporina Linnaeus, 1758) (Rodentia: Caviidae)

The red-rumped agouti is a small-sized wild rodent, belonging to the Dasyproctidae family, with great zootechnical potential, and it adapts well to captivity. In order to contribute to the species biology, this study describes the origin of the nerves forming the lumbosacral plexus. Twelve animals (six males and six females) were used, from previous experiments. The animals were fixed in a 10% formaldehyde aqueous solution and eviscerated after 72 hours. Then, the major and minor psoas muscles were retracted, exposing the nerves forming the plexus. Cotton soaked with 20-volume hydrogen peroxide was placed on these nerves, remaining for 12 hours straight for bleaching and subsequent dissection. The topographical relations of the lumbosacral plexus were grouped into tables and arranged in terms of simple percentage. In 7 cases (58.34%), the lumbosacral plexus in the red-rumped agouti stemmed from the ventral roots of the last 4 lumbar nerves and the first 3 sacral nerves (Type I – L4-S3), in 4 animals (33.33%) it stemmed from L5-S3 (Type II), and in 1 case (8.33%) it stemmed from L5-S4 (Type III). The nerves participating of the lumbosacral plexus in the red-rumped agouti were: lateral femoral cutaneous, genitofemoral, femoral, obturator, sciatic, cranial gluteal, caudal gluteal, and pudendal nerve. The origin of the lumbosacral plexus and the spinal nerves making up this plexus in red-rumped agoutis were similar to that described in other rodents, such as rock cavy, lowland paca and spix's yellow-toothed cavy.

Two-Year Outcome of Percutaneous Bipolar Radiofrequency Neurotomy of Sacral Nerves S2 and S3 in Spinal Cord Injured Patients with Neurogenic Detrusor Overactivity: A Randomized Controlled Feasibility Study

Background: Little research has been expended on the use of bipolar radiofrequency (RF) lesioning of sacral nerves in spinal cord injured (SCI) patients with neurogenic detrusor overactivity (NDO), and no study has been undertaken to demonstrate its long-term effect. Objective: To investigated the effect of bipolar RF ablation of the second and third sacral nerves over 2 years in SCI patients with NDO. Study Design: A prospective, randomized controlled feasibility study. Setting: The outpatient clinic of a single academic medical center in Korea. Methods: Ten SCI patients with NDO were recruited. These patients were randomly assigned to 2 groups; the intervention group (n = 5) and the control group (n = 5). Control group members received optimized conventional treatment. International Consultation on Incontinence Questionnaire (ICIQ), 3-day voiding diary, and the urinary incontinence quality of life scale (I-QOL) data were obtained at baseline and at 6, 12, and 24 months after intervention. Urodynamic study (UDS) was performed at baseline and 24 months after intervention. In the intervention group, percutaneous bipolar RF neurotomy was performed on both S2 and S3 nerves in each patient. Results: Frequency of urinary incontinence and ICIQ and IQOL scores showed significant effects for time and for the group x time interaction (P < 0.05). Daily mean volume of urinary incontinence showed only a significant group effect. In UDS parameters, comparisons of values at baseline and at 24 months revealed all variables showed significant intergroup differences (P < 0.05). Limitation: A small number of patients was recruited. Conclusion: Percutaneous bipolar RF ablation of sacral nerves S2 and S3 effectively reduces urinary incontinence and improves quality of life (QoL) in SCI patients with NDO and the effects lasted over 2 years. Key words: Neurogenic detrusor overactivity, bipolar RF neurotomy, sacral nerves, urinary incontinence, maximal detrusor pressure, maximum cystometric capacity

VARIABILITIES IN ANATOMICAL ARRANGEMENT OF SACRAL PLEXUS ROOTS. VARIACIONES EN LA DISPOSICIÓN ANATÓMICA DE LAS RAÍCES DEL PLEXO SACRO

Introducción. Las ramas del plexo sacro juegan un rol importante en la inervación motora y sensitiva del miembro inferior. En operaciones de la médula espinal observamos diversas variedades y nos motivó para iniciar este estudio dirigido a determinar la formación del plexo sacro desde la emergencia de cada raíz en los agujeros sacros hasta la formación de sus ramas terminales. Material y método. Se examinaron 100 plexos sacros en 50 cadáveres adultos con el propósito de determinar incidencia de las variaciones nerviosas. También consideramos el recorrido de sus ramas, sus anastomosis y grosor. Destacamos las particularidades de la inervación motora en el diagnóstico, además de la complejidad y variaciones anatómicas. Resultados. En general observamos 3 raíces sacras con la participación de S4 y el tronco lumbo-sacro de L4 y L5, y 4 nervios sacros. Habitualmente se observó un recorrido ascendente doble de la raíz S1, mientras que para las otras raíces la emergencia doble no fue común. El tronco lumbosacro se engrosó en 19 casos. La división muy alta del nervio ciático (en la pelvis menor) se observó en 2 casos. El nivel de ramificación de los otros nervios dependió del tipo de plexo. Conclusión. Nuestro estudio reveló variaciones relativamente frecuentes y variaciones anatómicas extraordinarias en la formación de las raíces nerviosas y la ramificación del plexo sacro. El conocimiento detallado de estas variaciones es útil para el propio diagnóstico y el tratamiento quirúrgico de las lesiones del plexo sacro y el dolor idiopático. Introduction. Branches of sacral plexus play an important role in the motor and sensory innervation of the lower limb. Various variations observed during the spinal operations have motivated us to start the study aimed on determination of the sacral plexus formation from its exit of particular roots from sacral foramina up to their formation into terminal branches. Material and method. One hundred sacral plexuses have been examined on 50 adult cadavers for a purpose to find out an incidence of its neural variations. We have considered also the course of their branches, the anatomoses and their thickness. We highlighted the motor innervation particularities in the relation to the diagnosis besides its anatomical complexity and variability. Results. Commonly were observed 3 sacral roots with the share of S4 and lumbosacral trunk of L4 and L5 and 4 sacral nerves. Doubled ascending course of S1 root was often observed, by the other sacral roots the doubled exit was not so frequent. Lumbosacral trunk was thickened in 19 cases. Very high division of the sciatic nerve (in the lesser pelvis) was observed in 2 cases. The branching off level of other nerves depended on the plexus type. Conclusion. Our study revealed a relatively frequent variabilities and described some extraordinary anatomical variations in the formation of nerve roots and branches of the sacral plexus. The detailed knowledge of these variabilities is useful for the proper diagnostics and surgical treatment of the sacral plexus injuries and unexplainable paient‘s complaints.