10-OS8-149_OA1 7/24/21 8:09 PM Page 62 Malaysian Orthopaedic Journal 2021 Vol 15 No 2 Krishnan A, et al doi: https://doi.org/10.5704/MOJ.2107.010 Thoracic Spine Stenosis: Does Ultrasonic Osteotome Improve Outcome in Comparison to Conventional Technique? Krishnan A, MS Orth, Samal P, MS Orth, Mayi S, MS Orth, Degulmadi D, MS Orth, Rai RR, MS Orth, Dave B, MS Orth Department of Spine Surgery, Stavya Spine Hospital and Research Institute, Ahmedabad, India This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited Date of submission: 27th December 2019 Date of acceptance: 25th May 2021 ABSTRACT INTRODUCTION Introduction: To investigate the efficacy of Ultrasonic Bone TSS with myelopathy is frequently associated with serious Scalpel (UBS) in thoracic spinal stenosis (TSS) in paralytic post-operative complications (11.5% to 33%) 1-3 . comparison to traditional technique. Injury due to ischemia and surgical manipulation are more Materials and methods: A total of 55 patients who had likely to occur in thoracic cord 1,2 . Better clinical outcome undergone conventional surgery (Group A) are compared depends on safely performing adequate neural with 45 patients of UBS (Group B) in TSS. The primary decompression. Traditionally nibbler, osteotome and/or outcome measure of Modified Japanese Orthopaedic Kerrison rongeur were used. The foot guard entering into the Association score (m JOA) with neurological complications already compromised neural canal repeatedly increases the and dural injury were assessed. Secondary outcome chances of injury. Over the past decades, the rotating burr measures of total blood loss (TBL), time duration of surgery and the motorised high-speed drill have evolved 4. They have (ORT) and length of hospital stay (LHS) were analysed. been the instruments of choice and has greatly improved the Results: The pre-operative mJOA score 5.00(4.00-6.00) in neurological outcomes. It has the disadvantages of being the the group A and 5.00(4.00-6.00) in the group B improved to rotating instrument, heating, may cause dural tear and being 7.00(7.00-8.00) in the group A and 9.00(9.00-10.00) in the time consuming 5,6 . Recent landmark innovation of UBS can group B, respectively (P<0.001) at final average follow-up of remarkably overcome the disadvantages of conventional and 117.55 months for group A and 75.69 months in group B. burr assisted surgeries 7,8 . But there are no reported studies of More significant grade of myelopathy improvement and UBS usage in TSS. mJOA recovery rate (RR) were noted in group B. The TBL, ORT and LHS were more favourable in group B as compared This study is a retrospective comparative evaluation of to group A (p<0.0001). The group A had 9 (16.36%) operated cases of TSS at our institute with conventional neurological deficits compared to 2 (4.44%) in group B technique and UBS technique to test the primary hypothesis (p<0.001). Dural tears occurred in both groups (A=11, B=9). that UBS improves the immediate perioperative outcomes in It was more frequent and not repairable in group A but terms of reduced incidence of dural injury and neurological without significant statistical difference. worsening. Thus, UBS contributes to more favourable final Conclusions: UBS can reduce neurological deficits and outcome. improve outcomes in TSS. Secondarily, reduced blood loss, lesser surgical time and reduced LHS are significant added advantages of this new technology. MATERIALS AND METHODS This study was approved by the institutional review board of Keywords: our hospital. Informed written consent was taken in all the spinal stenosis, thoracic, decompression, osteotome, patients. Between January 2004 and March 2014, a total 218 ultrasonic bone scalpel patients of TSS were operated at our spine centre who were reviewed retrospectively. Until 2011, we did decompression with conventional technique i.e with hand instruments only Corresponding Author: Ajay Krishnan, Department of Spine Surgery, Stavya Spine Hospital and Research Institute, Near Nagari Hospital, I P Mission Compound, Mithakhali, Ellisbridge, Ahmedabad, Gujarat 380007, India Email: [email protected] 62 10-OS8-149_OA1 7/24/21 8:09 PM Page 63 Ultrasonic scalpel thoracic laminectomy (Group A). From 2011 onward, we did decompression using The evaluation of immediate outcome was done with ultrasonic osteotome system [Misonix Bone Scalpel, occurrence of neurological deficit (partial/complete) and Misonix, and Farmingdale, NY, USA] (Group B). dural injury. mJOA score and its grading severity (A, B, C) was determined before and immediate after surgery, as well The patients included were, TSS patients without instability, as at the final follow-up visit. Post-operative neurological where only laminectomy and decompression procedure was recovery was estimated on the basis of the recovery rate done. Presence of instability and thoracic disc prolapsed or (RR) = (post-operative - pre-operative mJOA score) / (11- large ventral spurs lesions needing anterior decompression or pre-operative mJOA score) *100%. A score of 75–100% was fixations were excluded. Revision surgeries were excluded. designated as excellent, 50–74% good, 25–49% fair, and Medical records and image database of these befitting 0–24% poor 9. Additionally, total number of segment levels patients were reviewed for details i.e. demographics operated, ORT (minutes), time taken per segment of including age, gender, symptoms, duration of symptoms in laminectomy, TBL including intra operative blood loss pre-operative phase (in weeks), severity of symptoms and (IOBL), post-operative blood loss in drain (POBL), neurological deficits. Late presentation was tagged to the visualised epidural bleeding and blood loss per segment of patient if the surgery was done after 12 weeks of onset. The laminectomy and LHS were assessed. Intra-operative clinical status was further categorised according to the complications like dural thermal burns as visible blackening mJOA for thoracic myelopathy. Eleven is the highest of dura (UBS only), location/pattern of dural tear (linear or obtainable good score in severity and 0 is the lowest score. avulsion), its management, inadvertent over-cutting leading The severity of mJOA score was graded as mild (A;8–11), to spinal instability and any visible neural injury in both moderate (B;4–7), and severe (C;0–3) 9. groups were noted. The data, patient follow-up and images were collected and tabulated by surgeons who were not part Radiological assessment consisted of evaluating the spine of operating surgeon's team to avoid bias. If the old images radiographs, magnetic resonance imaging (MRI), MR were deficient then the previous radiological case reports myelograph in all cases and Computed Tomography (CT) were endorsed by consensus. When old images were not scan in few cases. The TSS diagnosis was further classified found for reconfirmation, then the interpretations entered in as due to ossified posterior longitudinal ligament (OPLL), operative note and case record were considered optimum. ossified ligamentum flavum (OLF), small ventral spurs (VS), hypertrophied ligamentum flavum (HLF) or Analysis of the patient’s demographics and characteristic combination of these. categorical variables were done. Mean (SD: Standard Deviation) for applicable variables were calculated. Median All the surgeries were performed by authors (BRD, AK). All (Inter-quartile range: IQR) were used for outcome patients were operated under general anaesthesia in prone parameters which were non-parametric. When data was not position. Injection methyl-prednisolone 1g dose (as institute normally distributed each category was compared by using protocol) was given intra-operatively. Exposure with suitable statistical tools such as Wilcoxon Test(W), Mann standard posterior midline approach was done. Blood Whitney test(U) and Chi-square test(X 2) for non-parametric pressure more than 100mm of Hg systolic was always data & unpaired ‘t’ test was used for parametric data. If the maintained. No neuro-monitoring was used. In group A, data was not normally distributed then non-parametric test laminectomy was performed with hand instruments i.e. values were used for comparison. Normality was checked Kerrison punches, nibbler, and/or osteotome. In group B, using Shapiro Wilks test. The significance of the relation was laminectomy was performed with the UBS. It has an considered in patients only if p<0.05. The software used is assembly of an ultrasonic generator which connects to the SPSS version 20.0. hand-piece with a disposable titanium cutting tip as the blade/shaver tip and irrigation tube/console. The blade works like an osteotome to make microscopic-precise cuts for en- RESULTS block removal of lamina. Post-operative spinal instability The study comprised of a total of 100 patients of TSS, who was avoided by removal of only medial one-third of the were operated and met the inclusion criteria. Out of the 218 facet. Layered surgical wound closure was done under a total patients, 118 who had stenosis due to infection, trauma, drain. If a linear dural tear was present, then it was secured disc prolapse or ventral stenosis with or without with intermittent sutures and repair was performed with 4-0 instrumented fusion were excluded. There was no significant Mersilk . In case of unrepairable dural avulsion fat graft difference in most demographic variables, sign/symptoms, /fascia graft or dural patch graft (G patch, Surgiwear, types of lesion and levels of pathology between both groups Ahmedabad, India) was put loosely and sutured. The drain (Table I, p value >0.05). So, both the groups were was removed on the third post-operative day. Routine comparable and homogenous. The study variables were painkillers and antibiotics were given. From the second post- analysed and summarised. operative day, as allowed by neurological status and motivation of patient, the mobilisation was started.