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Study Design:Systematic review.Objective:To date there is no consensus among surgeons as to what defines an MIS-TLIF (transforaminal lumbar interbody fusion using minimally invasive spine surgery) compared to an open or mini-open TLIF. This systematic review aimed to examine the MIS-TLIF techniques reported in the recent body of literature to help provide a definition of what constitutes the MIS-TLIF, based on the consensus of the majority of surgeons.Methods:We created a database of articles published about MIS-TLIF between 2010 and 2018. We evaluated the technical components of the MIS-TLIF including instruments and incisions used as well the order in which key steps are performed.Results:We could identify several patterns for MIS-TLIF performance that seemed agreed upon by the majority of MIS surgeons: use of paramedian incisions; use of a tubular retractor to perform a total facetectomy, decompression, and interbody cage implantation; and percutaneous insertion of the pedicle-screw rod constructs with intraoperative imaging.Conclusion:Based on this review of the literature, the key features used by surgeons performing MIS TLIF include the use of nonexpandable or expandable tubular retractors, a paramedian or lateral incision, and the use of a microscope or endoscope for visualization. Approaches using expandable nontubular retractors, those that require extensive subperiosteal dissection from the midline laterally, or specular-based retractors with wide pedicle to pedicle exposure are far less likely to be promoted as an MIS-based approach. A definition is necessary to improve the communication among spine surgeons in research as well as patient education.

Study Design: A retrospective single-center analysis of 159 cases. Objective: To investigate differences between male and female patients, as spinal infection (SI) represents a life-threatening condition and numerous factors may facilitate the course and outcome of SI, including patients’ age and comorbidities, as well as gender. To date, no comparative data investigating sex differences in SI is available. Thus, the purpose of the present retrospective trial was to investigate differences between male and female patients. Methods: A total of 159 patients who were treated for a spinal infection between 2010 and 2016 at our department were included in the analysis. The patients were categorized into 2 groups based on gender. Evaluation included magnetic resonance imaging, laboratory values, clinical outcome, and conservative/operative management. Results: Male patients suffered from SI significantly more often than female patients (n = 101, 63.5% vs n = 58, 36.5%, P = .001). However, female patients were initially affected more severely, as infection parameters were significantly higher ( P = .032) and vertebral destruction was more serious ( P = .018). Furthermore, women suffered from intraoperative complications more often ( P = .024) and received erythrocyte concentrates more frequently ( P = .01). Nevertheless, mortality rates and outcome were comparable. Pain scales were significantly higher in female patients at 12-month follow-up ( P = .042). Conclusion: Although male patients show a higher incidence for SI, the course of disease and the management is more challenging in female patients. Nevertheless, outcome after 12 months is comparably good. Underlying mechanisms may include a better immune response and dissimilar effects of antibiotic treatment in women. Pain management in female patients is still unsatisfactory after 12 months.

Objective The severe acute respiratory coronavirus 2 (SARS-CoV2) crisis led to many restrictions in daily life and protective health care actions in all hospitals to ensure basic medical supply. This questionnaire-based study among spinal surgeons in central Europe was generated to investigate the impact of coronavirus disease 2019 (COVID-19) and consecutively the differences in restrictions in spinal surgery units. Methods An online survey consisting of 32 questions on the impact of the COVID-19 pandemic and the related restrictions on spinal surgery units was created. Surgical fellows and consultants from neurosurgical, orthopedic, and trauma departments were included in our questionnaire-based study with the help of Austrian, German, and Swiss scientific societies. Results In a total of 406 completed questionnaires, most participants reported increased preventive measurements at daily clinical work (split-team work schedule [44%], cancellation of elective and/or semielective surgeries [91%]), reduced occurrence of emergencies (91%), decreased outpatient work (45%) with increased telemedical care (73%) and a reduced availability of medical equipment (75%) as well as medical staff (30%). Although most physicians considered the political restrictive decisions to be not suitable, most considered the medical measures to be appropriate. Conclusions The COVID-19 pandemic resulted in comparable restrictive measures for spinal surgical departments in central Europe. Elective surgical interventions were reduced, providing additional resources reserved for severe acute respiratory coronavirus 2–positive patients. Although similar restrictions were introduced in most participants' departments, the supply of personal protective equipment and the outpatient care remained insufficient and should be re-evaluated intensively for future global health care crises.

The negative impact on spinal diseases may apply not only to obesity but also to smoking. To investigate the influence of obesity and smoking on the development and recovery of lumbar disc herniation in young adults. Retrospective analysis of 97 patients who presented with lumbar disc herniation at the authors’ department between 2010 and 2017. Data were collected using the patients’ digital health records including demographics, clinical and neurological characteristics, treatment details, and outcomes. Ninety-seven patients between 17 and 25 years were included in this retrospective analysis. Patients were categorized into two groups according to their body mass index: obese (O, ≥ 30 kg/m2) and non-obese (NO, 2). The proportion of obese patients in our cohort vs. in the overall population differed significantly (19.4% vs. 3.8–7.1%, RR 3.17; p p = 0.067) and pain (p = 0.074). Also, the proportion of regular smokers differed significantly from the numbers of known smokers of the same age (62.4% vs. 30.2%, RR 2.0; p = 0.01). Obesity plus smoking showed a significantly negative impact on motor deficits postoperatively (p = 0.015) and at discharge (p = 0.025), as well as on pain values (p = 0.037) and on analgesic consumption (p = 0.034) at 6 weeks follow-up. The negative impact of obesity and smoking on the occurrence of lumbar disc herniation could be demonstrated for individuals aged 25 or younger. Furthermore, a trend to earlier recovery of motor deficits and significantly lower pain scales for non-obese and non-smoking patients could be shown.

Three-column osteotomy (3-CO) is a powerful technique in adult deformity surgery, and pedicle subtraction osteotomy (PSO) is the workhorse to correct severe kyphotic spinal deformities. Aging of the population, increasing cases of iatrogenic flat back deformities and understanding the importance of sagittal balance have led to a dramatic increase of this surgical technique. Surgery, however, is demanding and associated with high complication rates so that every step of the procedure requires meticulous technique. Particularly, osteotomy closure is associated with risks like secondary fracture, translation, or iatrogenic stenosis. This step is traditionally performed by compression or a cantilever maneuver with sometimes excessive forces on the screws or instrumentation. Implant loosening or abrupt subluxation resulting in construct failure and/or neurological deficits can result. The aim of this prospective registry study was to assess the efficacy and safety of our surgical PSO technique as well as the osteotomy closure by flexing a hinge-powered OR table. In a series of 84 consecutive lumbosacral 3-CO, a standardized surgical technique with special focus on closure of the osteotomy was prospectively evaluated. The surgical steps with the patients positioned prone on a soft frame are detailed. Osteotomy closure was achieved by remote controlled bending of a standard OR table without compressive or cantilever forces in all 84 cases. This technique carries a number of advantages, particularly the reversibility and the slow speed of closure with minimum force. There was not a single mechanical intraoperative complication such as vertebral body fracture, subluxation, or adjacent implant loosening during osteotomy closure, compared to external cohorts using the cantilever technique (p = 0.130). The feasibility of controlled 3-CO closure by flexing a standard OR table is demonstrated. This technique enables a safe, gentle closure of the osteotomy site with minimal risk of implant failure or accidental neurological injury.

Monostotic fibrous dysplasia (MFD) of the lumbar spine represents an exceedingly rare lesion. A 26-year-old patient presented with a progressive osteolytic lesion of the vertebral body L2 and the diagnosis of MFD. A minimally invasive left-sided eXtreme Lateral Interbody Fusion (XLIF) approach with resection of the vertebral body L2 with placement of a mesh cage was performed. No complications were observed perioperatively and the symptoms rapidly improved. Minimally invasive piecemeal resection with a combined dorsolateral approach showed a favorable clinical and radiological outcome and seems to be a safe and reliable technique for MFD.

Study Design: Technical note, retrospective case series. Objective: Lumbar stenosis can be effectively treated using tubular unilateral laminotomy for bilateral decompression (ULBD). For multilevel stenosis, a multilevel ULBD through separate, alternating crossover approaches has been described as the “slalom technique.” To increase efficacy, we introduced this approach with 2 microscopes simultaneously. Methods: We collected data on 13 patients, with multilevel lumbar stenosis, operated at our institution between 2015 and 2016 by the aforementioned technique. We assessed surgical time (ST), estimated blood loss (EBL), complications, and revision surgeries. Furthermore, we provide a stepwise instruction for performing the tandem microscopic slalom technique in a safe and efficient manner. Results: The mean age of the patients was 68 ± 8 years. The ST per level was 68 ± 19 minutes with an EBL per level of 39 ± 30 mL. We had no intraoperative complications and none of our patients required a revision surgery during a mean follow-up of 12 months. Conclusions: We have shown that this technique is feasible and can be performed safely for multisegmental lumbar spinal stenosis with minimal tissue trauma and low EBL. Furthermore, randomized controlled studies with a larger sample size may be necessary to drive any final conclusions.

Purpose Spinal infection (SI) is a life-threatening condition and treatment remains challenging. Numerous factors influence the outcome of SI and both conservative and operative care can be applied. As SI is associated with mortality rates between 2 and 20% even in developed countries, the purpose of the present study was to investigate the occurrence and causes of death in patients suffering from SI. Methods A retrospective analysis was performed on 197 patients, categorized into two groups according to their outcome: D (death) and S (survival). The diagnosis was based on clinical and imaging (MRI) findings. Data collected included demographics, clinical characteristics, comorbidities, infection parameters, treatment details, outcomes, and causes of death. Results The number of deaths was significantly higher in the conservative group (n = 9/51, 18%) compared with the operative counterpart (n = 8/146, 6%; p = 0.017). Death caused by septic multiorgan failure was the major cause of fatalities (n = 10/17, 59%) followed by death due to cardiopulmonary reasons (n = 4/17, 24%). The most frequent indication for conservative treatment in patients of group D included “highest perioperative risk” (n = 5/17, 29%). Conclusion We could demonstrate a significantly higher mortality rate in patients solely receiving conservative treatment. Mortality is associated with number and type of comorbidities, but also tends to be correlated with primarily acquired infection. As causes of death are predominantly associated with a septic patient state or progression of disease, our data may call for an earlier and more aggressive treatment. Nevertheless, prospective clinical trials will be mandatory to better understand the pathogenesis and course of spinal infection, and to develop high quality, evidence-based treatment recommendations.

Osteoporotic vertebral fractures are a widespread problem in the elderly population. In experienced hands, treatment procedures are safe and can be done in a minimally invasive fashion. Nevertheless, in rare cases, severe complications may occur. We present a case report of cement leakage after vertebroplasty of L5 compressing the nerve root with neurological signs and radiculopathy. An 86-year-old female patient was introduced to our department with severe L5 nerve root radiculopathy and a foot flexion paresis after vertebroplasty of L5. Computed tomography (CT) of the lumbar spine revealed extraforaminal extravasation of cement around the nerve root causing significant compression. The patient underwent surgical revision using spinal navigation for skin incision, retractor placing, and verification of the cement extravasation. The cement plombage was removed, and the patient improved immediately. Sufficient decompression of the nerve root after cement leakage can be achieved using a spinal navigation setup in combination with intraoperative CT.

Spinal infection (SI) is defined as an infectious disease affecting the vertebral body, the intervertebral disc, and/or adjacent paraspinal tissue and represents 2–7% of all musculoskeletal infections. There are numerous factors, which may facilitate the development of SI including not only advanced patient age and comorbidities but also spinal surgery. Due to the low specificity of signs, the delay in diagnosis of SI remains an important issue and poor outcome is frequently seen. Diagnosis should always be supported by clinical, laboratory, and imaging findings, magnetic resonance imaging (MRI) remaining the most reliable method. Management of SI depends on the location of the infection (i.e., intraspinal, intervertebral, paraspinal), on the disease progression, and of course on the patient’s general condition, considering age and comorbidities. Conservative treatment mostly is reasonable in early stages with no or minor neurologic deficits and in case of severe comorbidities, which limit surgical options. Nevertheless, solely medical treatment often fails. Therefore, in case of doubt, surgical treatment should be considered. The final result in conservative as well as in surgical treatment always is bony fusion. Furthermore, both options require a concomitant antimicrobial therapy, initially applied intravenously and administered orally thereafter. The optimal duration of antibiotic therapy remains controversial, but should never undercut 6 weeks. Due to a heterogeneous and often comorbid patient population and the wide variety of treatment options, no generally applicable guidelines for SI exist and management remains a challenge. Thus, future prospective randomized trials are necessary to substantiate treatment strategies.

Background Intervertebral disc degeneration is one of the most common reasons for chronic low back pain and sensomotoric deficits, often treated by lumbar sequestrectomy. Nevertheless, the prognostic factors relevant for time and quality of recovery, of the surgical procedure, relative to conservative treatment, remain controversial and require further investigation. Surface electrical stimulation (SES) may be an influential intervention, already showing positive impact on motor and sensory recovery in different patient groups. Since mechanisms of SES still remain unclear, further inquiry is needed. Methods/Design This is a prospective, monocentric, randomized, controlled clinical trial. A total of 80 adult patients suffering from a lumbar disc herniation (LDH; 40 treated surgically, 40 conservatively) are allocated in a ratio of 1:1. Patients in the treatment group will receive surface electromyography (EMG)-triggered electrical stimulation for eight weeks, whereas patients in the control group will not obtain any additional treatment. The primary outcome parameter is defined as the cold detection threshold (CDT), determined by quantitative sensory testing (QST), 24 months after intervention. Secondary outcome parameters include the inquiry of sensory nerve function by two-point discrimination and QST, the assessment of motor nerve function by manual muscle testing, and validated scales and scores. These include: the Oswestry Disability Index (ODI) and the Core Outcome Measures Index (COMI) assessing the domains pain, back-specific function, work disability, and patient satisfaction; the EQ-5D investigating the patient’s generic health status; the painDETECT questionnaire (PD-Q) to identify neuropathic pain components; and the Beck Depression Inventory (BDI) to assess severity of depression. Moreover, neurological status, pain medication usage, and blood samples (CRP, TNFα, IL-1β, IL-6) will be evaluated. Study data generation (study site) and data storage, processing, and statistical analysis are clearly separated. Discussion The results of the RECO study will detect the effect of EMG-triggered multichannel SES on the improvement of mechanical and thermal sensitivity and the effect on motor recovery and pain, associated with clinical and laboratory parameters. Furthermore, data comparing surgical and conservative treatment can be collected. This will hopefully allow treatment recommendations for patients with LDH accompanied by a sensomotoric deficit. Trial registration ISRCTN, ISRCTN12741173. Registered on 15 January 2017. Electronic supplementary material The online version of this article (doi:10.1186/s13063-017-2310-z) contains supplementary material, which is available to authorized users.

Cervical corpectomies are increasingly used to treat degenerative, metastatic, inflammatory and traumatic multisegmental diseases. The postoperative results are thought to correlate mainly with the number of resected vertebral bodies. Thus, the aim of the study was to analyse complications and early outcome of these procedures to document the implant-related complications in order to set up a prospective clinical trial. Forty-five patients, who were treated in our department from 2011 to 2014 and who were available for a minimum follow-up of 1 year, were consecutively included in this retrospective evaluation. The median age was 61 (±11) years with a female to male sex ratio of 19 to 26, respectively. In these patients, cervical corpectomies (one-, two- and three-level procedures) were performed. The average number of resected levels was 1.2 levels. The intraoperative loss of blood (LOB), the red cell transfusions (rcT), the length of operation (LOO) and the usage of drains were investigated and correlated with intra- and postoperative complications. The mean LOO was 244 min (±68) with a mean LOB of 511 ml (±531). The overall complication rate was 22.9% (10 patients). Six patients (13.3%) had implant-related complications due to loosening and toggling of the screws and/or cage subsidence. Two patients (4.4%) had a postoperative haematoma and another two patients (4.4%) suffered from neurological deterioration due to an ongoing and severe myelopathic syndrome. All these patients received revision surgery. The average time from the first to revision surgery was 90 days. Cervical corpectomies still remain procedures with a high complication rate mainly represented by implant-related failures. These implant-related complications range from screw/plate loosening or toggling to graft dislocation with subsidence and might be associated with constructs extended to the C7 vertebral body. In our study population, the rate of implant failure was comparable to the literature, but not obviously correlated with the number of vertebral bodies resected. This may be attributed to the different disease entities. Thus, our results support the use of circumferential approaches for selected instability scenarios (metastatic or inflammatory diseases, kyphosis, osteoporosis, etc.) of one- and two-level corpectomies.

Spondylodiscitis may arise primarily via hematogenous spread or direct inoculation of virulent organisms during spine surgery. To date, no comparative data investigating the differences between primary and postoperative spondylodiscitis is available. Thus, the purpose of this retrospective study was to investigate differences between these two etiologies. One hundred fifty-nine patients that were treated at our department were included in the retrospective analysis. The patients were categorized into two groups based on the etiology of spondylodiscitis: group NS, primary spondylodiscitis without prior spinal surgery; group S, spondylodiscitis following spinal surgery. Evaluation included magnetic resonance imaging (MRI), laboratory values, clinical outcome, and operative or conservative management. Preoperative MRI showed higher rates of epidural and paraspinal abscess in patients with primary spondylodiscitis (p

Symptomatic lumbar spondylolisthesis is commonly accompanied by spinal stenosis in multiple segments. These pathologies are routinely treated by multilevel decompression and instrumented fusion. However, it was hypothesized that a minimally invasive surgery (MIS) fusion in the unstable segment combined with a unilateral laminotomy for bilateral decompression (ULBD) in the adjacent stenotic segment is a biomechanically feasible alternative to a two-level fusion and superior to open laminectomy adjacent to a fused segment. This concept has demonstrated success in a recently published biomechanical cadaver study performed by our group. The present article offers a detailed step by step technical description for an MIS-TLIF (transforaminal lumbar interbody fusion) with adjacent ULBD.

The improvement of pain and functionality is the major goal of a surgical intervention. Thus, the purpose of the present prospective study was to evaluate whether subjective sensory deficits in patients with lumbar radiculopathy caused by a lumbar disc herniation are related to clinical status, using several outcome scores and the quantitative sensory testing (QST) pre- and 12 months postoperatively. We applied the QST in 52 patients with a single lumbar disc herniation treated by lumbar sequestrectomy pre- and 12 months postoperatively. Further evaluation included numeric rating scale (NRS) for leg, EuroQoL-5D (EQ-5D), Core Outcome Measure Index (COMI), Oswestry Disability Index (ODI), Beck Depression Inventory (BDI) and PaindDetect questionnaire (PD-Q). Patients were then categorized into two groups based on their subjective recovery of sensory function. The patients’ self-assessment and QST were correlated with each other for the pre- and postoperative visit after 12 months. The two groups showed postoperative differences in mechanical and vibration detection threshold as well as in the postoperative PD-Q (p

Previous studies have investigated sensory recovery in patients with lumbar disc herniation using rather subjective methods. There have been no reports on changes of sensory function in patients suffering from a preoperative sensory deficit using quantitative sensory testing (QST). The aims of this prospective study were (1) to assess the recovery of preoperative sensory dysfunction after lumbar sequestrectomy and (2) to quantify the strength of relationship between a sensory deficit and the patient’s quality of life. We applied the QST protocol of the German Research Network on Neuropathic Pain (DFNS) in fifty-two patients with a single lumbar disc herniation confirmed on MRI treated by lumbar sequestrectomy. Further evaluation included a detailed medical history, a physical examination, numeric rating scale for leg, EQ-5D questionnaire, and thermometer. Disc surgery resulted in a significant reduction of leg pain and a significant gain of quality of life. Thermal, mechanical, and vibration perception thresholds showed an obvious side-to-side difference preoperatively (p

Background Minimally invasive surgical techniques have been developed to minimize tissue damage, reduce narcotic requirements, decrease blood loss, and, therefore, potentially avoid prolonged immobilization. Thus, the purpose of the present retrospective study was to assess the safety and efficacy of a minimally invasive posterior approach with transforaminal lumbar interbody debridement and fusion plus pedicle screw fixation in lumbar spondylodiscitis in comparison to an open surgical approach. Furthermore, treatment decisions based on the patient´s preoperative condition were analyzed. Methods 67 patients with lumbar spondylodiscitis treated at our department were included in this retrospective analysis. The patients were categorized into two groups based on the surgical procedure: group (MIS) minimally invasive lumbar spinal fusion (n = 19); group (OPEN) open lumbar spinal fusion (n = 48). Evaluation included radiological parameters on magnetic resonance imaging (MRI), laboratory values, and clinical outcome. Results Preoperative MRI showed higher rates of paraspinal abscess (35.5 vs. 5.6%; p = 0.016) and multilocular location in the OPEN group (20 vs. 0%, p = 0.014). Overall pain at discharge was less in the MIS group: NRS 2.4 ± 1 vs. NRS 1.6 ± 1 (p = 0.036). The duration of hospital stay was longer in the OPEN than the MIS group (19.1 ± 12 days vs. 13.7 ± 5 days, p = 0.018). Conclusion The open technique is effective in all varieties of spondylodiscitis inclusive in epidural abscess formation. MIS can be applied safely and effectively as well in selected cases, even with epidural abscess.

Background Spinal fusion with pedicle screw fixation represents the gold standard for lumbar degenerative disc disease with instability. Although it is an established technique, it is nevertheless an invasive intervention with high complication rates. Therefore, minimally invasive approaches have been developed, the medialized bilateral screw pedicel fixation (mPACT) being one of them. The study objective is to evaluate prospectively the efficacy and safety of the mPACT technique compared with the traditional trajectory for degenerative lumbar spondylolisthesis. Methods/design This is a single-center, randomized, controlled, parallel group, superiority trial. A total of 154 adult patients are allocated in a ratio of 1:1. Sample size and power calculation were performed to detect the minimal clinically important difference of 10%, with an expected standard deviation of 20% in the primary outcome parameter, the Oswestry Disability Index, with power of 80%, based on an assumed maximal dropout rate of 20%. Secondary outcome parameters include the EuroQoL 5-Dimension questionnaire, the Beck Depression Inventory, the painDETECT questionnaire and the “timed up and go” test. Furthermore, radiological and health economic outcomes will be evaluated. Follow up is performed until 5 years after surgery. Major inclusion criteria are lumbar degenerative spondylolisthesis with Meyerding grade I or II, which qualifies for decompression and fusion by medialised posterior screw placement with cortical trajectory (mPACT) or by a traditional trajectory for lumbar pedicle screw placement. Discussion This trial will contribute to the understanding of the short-term and long-term clinical and radiological postoperative course in patients with lumbar degenerative disc disease, in which the mPACT technique is used. Trial registration ISRCTN registry, ISRCTN99263604. Registered on 3 November 2016. Electronic supplementary material The online version of this article (10.1186/s13063-018-2504-z) contains supplementary material, which is available to authorized users.

A lumbar disc herniation resulting in surgery may be an incisive event in a patient’s everyday life. The patient’s recovery after sequestrectomy may be influenced by several factors. There is evidence that regular physical activity can lower pain perception and improve the outcome after surgery. For this purpose, we hypothesized that patients performing regular sports prior to lumbar disc surgery might have less pain perception and disability thereafter. Fifty-two participants with a single lumbar disc herniation confirmed on MRI treated by a lumbar sequestrectomy were included in the trial. They were categorized into two groups based on their self-reported level of physical activity prior to surgery: group NS, no regular physical activity and group S, with regular physical activity. Further evaluation included a detailed medical history, a physical examination, and various questionnaires: Visual Analog Scale (VAS), Beck-Depression-Inventory (BDI), Oswestry Disability Index (ODI), Core Outcome Measure Index (COMI), and the EuroQoL-5Dimension (EQ- 5D). Surgery had an excellent overall improvement of pain and disability (p

Quantitative sensory testing (QST) gained popularity to evaluate the time course of recovery in sensory dysfunction and the results of different treatment options. Concerning sex differences in lumbar spine surgery, female gender seems to play a major role as a negative prognostic factor in different spinal disorders. For this purpose, we hypothesised that there are also comparable differences in pain patterns in men and women after lumbar sequestrectomy using QST. We applied the QST protocol of the German Research Network on Neuropathic Pain in 53 patients (21 women and 32 men) with a single lumbar disc herniation confirmed on MRI treated by a lumbar sequestrectomy. Further evaluation included a detailed medical history, a physical examination, and various questionnaires: Beck-Depression-Inventory, Oswestry Disability Index, Core Outcome Measure Index, painDETECT-Questionnaire and EQ-5D thermometer. Our analyses showed lower heat thresholds in females preoperatively, that adjusted to that of males 1 week postoperatively. Pressure pain thresholds were lower in women as well, but differed between genders throughout the study. Vibration perception deficits resolve earlier in female than in male patients. Both, women and men, had an excellent overall improvement, postoperatively. Our results clearly revealed pre- and postoperative differences in pain perception between genders. These differences have to be taken into account in the evaluation of outcome between genders. Therefore, QST seems to be a good method to evaluate the time course of recovery after surgery.