3D printer

3D printer

see 3D printing.

A 3D printer is a type of industrial robot.


Developing new surgical instruments is challenging. While making surgical instruments could be a good field of application for 3D printers, attempts to do so have proven limited.

Yang et al. designed a new endoscope-assisted spine surgery system, and using a 3D printer, attempted to create a complex surgical instrument and to evaluate the feasibility thereof. Developing the new surgical instruments using a 3D printer consisted of two parts: one part was the creation of a prototype instrument, and the other was the production of a patient model.

They designed a new endoscope-assisted spine surgery system with a cannula for the endoscope and working instruments and extra cannula that could be easily added. Using custom-made patient-specific 3D models, they conducted discectomies for paramedian and foraminal discs with both the newly designed spine surgery system and conventional tubular surgery. The new spine surgery system had an extra portal that can be well bonded in by a magnetic connector and greatly expanded the range of access for instruments without unnecessary bone destruction. In a foraminal discectomy, the newly designed spine surgery system showed less facet resection, compared to conventional surgery.

They were able to develop and demonstrate the usefulness of a new endoscope-assisted spine surgery system relying on 3D printing technology. Using the extra portal, the usability of endoscope-assisted surgery could be greatly increased. They suggested that 3D printing technology can be very useful for the realization and evaluation of complex surgical instrument systems 1).


Disruptive technologies are rare phenomena. However, when they do come about, they have the potential to change the course of entire industries. Such is the case with the new three-dimensional (3D) printing technology from Carbon3D Inc. (Redwood City, California, USA), dubbed Continuous Liquid Interface Production (CLIP). With its innovative approach to additive manufacturing, CLIP has the potential to usurp and revolutionize 3D printing, with reverberations into several fields, including neurologic surgery 2).

A technique using an industrial rapid prototyping process by three-dimensional (3D) printing was developed, from which accurate spatial models of the nasal cavity, paranasal sinuses (sphenoid sinus in particular), and intrasellar/pituitary pathology were produced, according to the parameters of an individual patient. Image-guided surgical (IGS) techniques on two different platforms were used during endoscopic transsphenoidal surgery to test and validate the anatomical accuracy of the sinus models by comparing the models with radiological images of the patient on IGS. RESULTS: It was possible to register, validate, and navigate accurately on these models using commonly available navigation stations, matching accurately the anatomy of the model to the IGS images 3)

Neurosurgeons regularly plan their surgery using magnetic resonance imaging (MRI) images, which may show a clear distinction between the area to be resected and the surrounding healthy brain tissue depending on the nature of the pathology. However, this distinction is often unclear with the naked eye during the surgical intervention, and it may be difficult to infer depth and an accurate volumetric interpretation from a series of MRI image slices.

MRI data are used to create affordable patient-specific 3-dimensional (3D) scale models of the brain which clearly indicate the location and extent of a tumour relative to brain surface features and important adjacent structures.

This is achieved using custom software and rapid prototyping. In addition, functionally eloquent areas identified using functional MRI are integrated into the 3D models.

Preliminary in vivo results are presented for 2 patients. The accuracy of the technique was estimated both theoretically and by printing a geometrical phantom, with mean dimensional errors of less than 0.5 mm observed.

This may provide a practical and cost-effective tool which can be used for training, and during neurosurgical planning and intervention 4).

The advent of multimaterial 3D printers allows the creation of neurosurgical models of a more realistic nature, mimicking real tissues. Warren et al. used the latest generation of 3D printer to create a model, with an inbuilt pathological entity, of varying consistency and density. Using this model the authors were able to take trainees through the basic steps, from navigation and planning of skin flap to performing initial steps in a craniotomy and simple tumor excision. As the technology advances, models of this nature may be able to supplement the training of neurosurgeons in a simulated operating theater environment, thus improving the training experience 5).

Articles

Aoun RJ, Hamade YJ, Zammar SG, Patel NP, Bendok BR. Futuristic Three-Dimensional Printing and Personalized Neurosurgery. World Neurosurg. 2015 Oct;84(4):870-1. doi: 10.1016/j.wneu.2015.08.010. Epub 2015 Aug 20. PubMed PMID: 26299265 6).

Indications

Large format (ie, >25 cm) cranioplasty is a challenging procedure not only from a cosmesis standpoint, but also in terms of ensuring that the patient’s brain will be well-protected from direct trauma. Until recently, when a patient’s own cranial flap was unavailable, these goals were unattainable. Recent advances in implant computer-aided design and 3-dimensional (3-D) printing are leveraging other advances in regenerative medicine. It is now possible to 3-D-print patient-specific implants from a variety of polymer, ceramic, or metal components. A skull template may be used to design the external shape of an implant that will become well integrated in the skull, while also providing beneficial distribution of mechanical force in the event of trauma. Furthermore, an internal pore geometry can be utilized to facilitate the seeding of banked allograft cells. Implants may be cultured in a bioreactor along with recombinant growth factors to produce implants coated with bone progenitor cells and extracellular matrix that appear to the body as a graft, albeit a tissue-engineered graft. The growth factors would be left behind in the bioreactor and the graft would resorb as new host bone invades the space and is remodeled into strong bone. As described in a review, such advancements will lead to optimal replacement of cranial defects that are both patient-specific and regenerative 7).

References

1)

Yang HS, Park JY. 3D Printer Application for Endoscope-Assisted Spine Surgery Instrument Development: From Prototype Instruments to Patient-Specific 3D Models. Yonsei Med J. 2020 Jan;61(1):94-99. doi: 10.3349/ymj.2020.61.1.94. PubMed PMID: 31887805.
2) , 6)

Aoun RJ, Hamade YJ, Zammar SG, Patel NP, Bendok BR. Futuristic Three-Dimensional Printing and Personalized Neurosurgery. World Neurosurg. 2015 Oct;84(4):870-1. doi: 10.1016/j.wneu.2015.08.010. Epub 2015 Aug 20. PubMed PMID: 26299265.
3)

Waran V, Menon R, Pancharatnam D, Rathinam AK, Balakrishnan YK, Tung TS, Raman R, Prepageran N, Chandran H, Rahman ZA. The creation and verification of cranial models using three-dimensional rapid prototyping technology in field of transnasal sphenoid endoscopy. Am J Rhinol Allergy. 2012 Sep-Oct;26(5):e132-6. doi: 10.2500/ajra.2012.26.3808. PubMed PMID: 23168144.
4)

Spottiswoode BS, van den Heever DJ, Chang Y, Engelhardt S, Du Plessis S, Nicolls F, Hartzenberg HB, Gretschel A. Preoperative three-dimensional model creation of magnetic resonance brain images as a tool to assist neurosurgical planning. Stereotact Funct Neurosurg. 2013;91(3):162-9. doi: 10.1159/000345264. Epub 2013 Feb 27. PubMed PMID: 23446024.
5)

Waran V, Narayanan V, Karuppiah R, Owen SL, Aziz T. Utility of multimaterial 3D printers in creating models with pathological entities to enhance the training experience of neurosurgeons. J Neurosurg. 2014 Feb;120(2):489-92. doi: 10.3171/2013.11.JNS131066. Epub 2013 Dec 10. PubMed PMID: 24321044.
7)

Bonda DJ, Manjila S, Selman WR, Dean D. The Recent Revolution in the Design and Manufacture of Cranial Implants: Modern Advancements and Future Directions. Neurosurgery. 2015 Nov;77(5):814-24. doi: 10.1227/NEU.0000000000000899. PubMed PMID: 26171578; PubMed Central PMCID: PMC4615389.

Intrathecal morphine for Restless Legs Syndrome

Intrathecal morphine for Restless Legs Syndrome

For those who suffer from a medically refractory Restless Legs Syndrome (RLS), intrathecal morphine treatment has been shown to be effective. The aim of a retrospective study of Steensland et al. was to investigate efficacy, complications and side effects in patients treated over several years with an implantable pump. A comparison was done to a group of patients treated with a similar pump system due to spasticity.

The charts of ten patients with severe or very severe RLS have been reviewed. These patients have received an intrathecal drug delivery system during 2000 -2016. To compare the rate of complications, a control group of 20 patients treated with intrathecal baclofen due to spasticity was included in the study. Their time of treatment corresponded to the RLS patients’.

The severity of symptoms related to RLS decreased significantly after treatment. Doses required ranged from 68 to 140 µg/day. Two cases of side effects were detected; one case with nausea and dizziness and one case with headache and fatigue. The rate of mechanical-, infectious- and other complications were similar between the two groups.

In light of the decrease in symptom severity and the low rate of side effects, intrathecal morphine can be considered an adequate treatment for those suffering from medically refractory RLS. The occurrence of complications did not differ between subjects with RLS and spasticity 1).

Case reports

Three patients with medically refractory RLS received an implanted pump for delivery of intrathecal morphine. Severity of RLS and self-assessed health were rated using the International Restless Legs Syndrome Study Group (IRLSSG) rating scale and the Short Form health survey (SF-36). Assessments were made preoperatively and after 6 months of follow-up.

Preoperatively two patients had very severe RLS, scoring 35 and 36 on the IRLSSG rating scale, and one patient had severe RLS (score, 26). All three patients were free of symptoms of RLS post-operatively and also at the 6-month follow-up. The daily doses of intrathecal morphine ranged from 73 to 199 µg. Results from the SF-36 health survey showed that all three patients had a better physical health compared to before surgery.

Intrathecal morphine may be efficient in the treatment for medically refractory RLS. All three patients became completely free of symptoms, and there was also improvement in self-perceived overall health 2)


In 2012 case reports of 4 patients documented excellent results with short-term use of intrathecal opioids also in RLS 3).


In 2008 Ross et al. reported the successful use of low-dose intrathecal morphine in a severe case of restless legs syndrome refractory to medication.

The surgery was complicated by extreme restlessness in the recovery room resulting in withdrawal or breakage of the catheter on multiple occasions. Relief of symptoms was lost with each catheter malfunction. They describes the possible origin of this complication and a solution to the problem resulting in the successful control of symptoms for 7 months since the last surgery. 4).

They are, however, wrong in their statement that this is the third published case of this particular treatment. In an article in the Swedish medical journal Lakartidningen 5), Lindvall et al. previously accounted for 7 patients with refractory restless legs syndrome who were successfully treated with intrathecal morphine. An abstract in English is available through the official web site of this journal, and the article is indexed by PubMed. The 7 patients were treated at 3 hospitals in the northern region of Sweden, which is covered by the neurosurgical department of Umeå University Hospital 6).


In 2002 two patients with incapacitating symptoms from restless legs syndrome, not adequately responding to conventional treatment with dopaminergic drugs, were implanted with a pump device (Isomed) for intrathecal delivery of morphine and bupivacaine. The treatment resulted in total resolution of all symptoms with few side effects 7).

References

1)

Steensland I, Koskinen LD, Lindvall P. Treatment of Restless legs with a pump; efficacy and complications. Acta Neurol Scand. 2019 Dec 28. doi: 10.1111/ane.13213. [Epub ahead of print] PubMed PMID: 31883387.
2)

Lindvall P, Hariz GM, Blomstedt P. Overall self-perceived health in Restless legs treated with intrathecal morphine. Acta Neurol Scand. 2013 Apr;127(4):268-73. doi: 10.1111/j.1600-0404.2012.01707.x. Epub 2012 Aug 9. PubMed PMID: 22881705.
3)

Hornyak M, Kaube H. Long-Term treatment of a patient with severe restless legs syndrome using intrathecal morphine. Neurology. 2012 Dec 11;79(24):2361-2. doi: 10.1212/WNL.0b013e318278b5e7. Epub 2012 Nov 28. PubMed PMID: 23197746.
4)

Ross DA, Narus MS, Nutt JG. Control of medically refractory restless legs syndrome with intrathecal morphine: case report. Neurosurgery. 2008 Jan;62(1):E263; discussion E263. doi: 10.1227/01.NEU.0000311089.04014.91. PubMed PMID: 18300885.
5)

Lindvall PK, Ruuth K, Jakobsson B, Nilsson SK. [Intrathecal morphine infusion a possible treatment in restless legs]. Lakartidningen. 2007 Aug 8-21;104(32-33):2250-2. Swedish. PubMed PMID: 17822205.
6)

Lindvall P, Ruuth K, Jakobsson B, Nilsson S. Intrathecal morphine as a treatment for refractory restless legs syndrome. Neurosurgery. 2008 Dec;63(6):E1209; author reply E1209. doi: 10.1227/01.NEU.0000325674.02282.CC. PubMed PMID: 19057291.
7)

Jakobsson B, Ruuth K. Successful treatment of restless legs syndrome with an implanted pump for intrathecal drug delivery. Acta Anaesthesiol Scand. 2002 Jan;46(1):114-7. PubMed PMID: 11903084.

Frame-based stereotactic biopsy

Frame-based stereotactic biopsy

Frame based stereotactic biopsy (FSB) remains the ‘gold standard’ for obtaining diagnostic samples of intracranial lesions to guide therapy. Nevertheless, diagnostic yield is highly variable.

The diagnostic yield from contemporary FSB is high and is dependent predominantly on lesion size. 1).

Complications

Case series

retrospective cohort study was conducted of all adult patients with imaging-documented lesions undergoing FSB at the Beth Israel Deaconess Medical Center between 20132018. Diagnostic accuracy, lesion characteristics associated with non-diagnostic biopsy, and surgical complications were evaluated. A biopsy was considered non-diagnostic if all frozen samples and the final pathology yielded normal brain tissue or non-specific reactive tissue unless the “reactive” pathology was consistent with radiation injury from prior therapy.

This search identified 198 FSB patients. Mean (SD) age was 62±17 years and 44.2% were female. The median procedure time was 32 minutes. A definitive histologic diagnosis was established in 187 cases (94.4% diagnostic yield). The mean lesion diameter was 31.9±16.8 mm. Multivariable logistic regression revealed only lesion diameter to be significantly associated with a diagnostic result (OR for the non-diagnostic result: 0.94 per mm diameter decrease, 95% CI 0.87-0.99, P=0.028). On univariable analysis, the diagnosis of CNS lymphoma appeared to increase the risk of a non-diagnostic biopsy (P=0.025), but this association disappeared when controlling for lesion size and steroid administration prior to biopsy. Eight patients (4.0%) developed postoperative hemorrhagic complications, three of whom required reoperation, and another expired.

This study demonstrates that diagnostic yield from contemporary FSB is high and is dependent predominantly on lesion size. 2).


Hamisch et al. evaluated the feasibility, safety, and diagnostic yield of frame-based stereotactic biopsies (SB) in lesions located in deep-seated and midline structures of the brain to analyze these parameters in comparison to other brain areas.

In a retrospective, tertiary care single-center analysis, they identified all patients who received SB for lesions localized in deep-seated and midline structures (corpus callosum, basal ganglia, pineal region, sella, thalamus, and brainstem) between January 1996 and June 2015. Study participants were between 1 and 82 years. We evaluated the feasibility, procedural complications (mortality, transient and permanent morbidity), and diagnostic yield. We further performed a risk analysis of factors influencing the latter parameters. Chi-square test, Student t test, and Mann-Whitney rank-sum test were used for statistical analysis.

Four hundred eighty-nine patients receiving 511 SB procedures (median age 48.5 years, range 1-82; median Karnofsky Performance Score 80%, range 50-100%, 43.8% female/56.2% male) were identified. Lesions were localized in the corpus callosum (29.5%), basal ganglia (17.0%), pineal region (11.5%), sella (7.8%), thalamus (4.3%), brainstem (28.8%), and others (1.1%). Procedure-related mortality was 0%, and permanent morbidity was 0.4%. Transient morbidity was 9.6%. Histological diagnosis was possible in 99.2% (low-grade gliomas 16.2%, high-grade gliomas 40.3%, other tumors in 27.8%, no neoplastic lesions 14.5%, no definitive histological diagnosis 0.8%). Only the pons location correlated significantly with transient morbidity (p < 0.001).

In experienced centers, frame-based stereotactic biopsy is a safe diagnostic tool with a high diagnostic yield also for deep-seated and midline lesions 3).


A report described the methodology, diagnostic yield, and adverse events (AE) associated with frame-based stereotactic brain biopsies (FBSB) obtained from 26 dogs with solitary forebrain lesions. Medical records were reviewed from dogs that underwent FBSB using two stereotactic headframes designed for use in small animals and compatible with computed tomographic (CT) and magnetic resonance (MR) imaging. Stereotactic plans were generated from MR and CT images using commercial software, and FBSB performed both with (14/26) and without intraoperative image guidance. Records were reviewed for diagnostic yield, defined as the proportion of biopsies producing a specific neuropathological diagnosis, AE associated with FBSB, and risk factors for the development of AE. Postprocedural AE were evaluated in 19/26 dogs that did not proceed to a therapeutic intervention immediately following biopsy. Biopsy targets included intra-axial telencephalic masses (24/26), one intra-axial diencephalic mass, and one extra-axial parasellar mass. The median target volume was 1.99 cm(3). No differences in patient, lesion, or outcome variables were observed between the two headframe systems used or between FBSB performed with or without intraoperative CT guidance. The diagnostic yield of FBSB was 94.6%. Needle placement error was a significant risk factor associated with procurement of non-diagnostic biopsy specimens. Gliomas were diagnosed in 24/26 dogs, and meningioma and granulomatous meningoencephalitis in 1 dog each. AE directly related to FBSB were observed in a total of 7/26 (27%) of dogs. Biopsy-associated clinical morbidity, manifesting as seizures and transient neurological deterioration, occurred in 3/19 (16%) of dogs. The case fatality rate was 5.2% (1/19 dogs), with death attributable to intracranial hemorrhage. FBSB using the described apparatus was relatively safe and effective at providing neuropathological diagnoses in dogs with focal forebrain lesions 4).

Grand Challenge Veterinary Neurology and Neurosurgery: Veterinary Neurology and Neurosurgery – Research for Animals and Translational Aspects 5).

References

1) , 2)

Maragkos GA, Penumaka A, Ahrendsen JT, Salem MM, Nelton EB, Alterman RL. Factors Affecting the Diagnostic Yield of Frame-Based Stereotactic Intracranial Biopsies. World Neurosurg. 2019 Dec 25. pii: S1878-8750(19)33134-1. doi: 10.1016/j.wneu.2019.12.102. [Epub ahead of print] PubMed PMID: 31883483.
3)

Hamisch CA, Minartz J, Blau T, Hafkemeyer V, Rueß D, Hellerbach A, Grau SJ, Ruge MI. Frame-based stereotactic biopsy of deep-seated and midline structures in 511 procedures: feasibility, risk profile, and diagnostic yield. Acta Neurochir (Wien). 2019 Jul 29. doi: 10.1007/s00701-019-04020-1. [Epub ahead of print] PubMed PMID: 31359191.
4)

Rossmeisl JH, Andriani RT, Cecere TE, Lahmers K, LeRoith T, Zimmerman KL, Gibo D, Debinski W. Frame-Based Stereotactic Biopsy of Canine Brain Masses: Technique and Clinical Results in 26 Cases. Front Vet Sci. 2015 Jul 27;2:20. eCollection 2015. PubMed PMID: 26664949.
5)

Tipold A. Grand Challenge Veterinary Neurology and Neurosurgery: Veterinary Neurology and Neurosurgery – Research for Animals and Translational Aspects. Front Vet Sci. 2015 May 26;2:13. eCollection 2015. PubMed PMID: 26664942.

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