A new minimal-invasive approach for total hip replacement in sheep.

BACKGROUND: Over the last 50 years arthroplasty became the gold-standard treatment for disabling conditions of the coxofemoral joint. Variations of anterior, lateral, and dorsal incision have been applied, but as each approach requires the incision and reflection of various muscles to gain adequate exposure of the joint results are still controversial. OBJECTIVE: The purpose of this study was to develop a minimal-invasive, tissue-sparing approach in sheep with reduced risks in animal testing. METHODS: 12 mature sheep underwent hip surgery as part of a study to evaluate a hip resurfacing system. In line with the preliminary cadaveric tests a modified, minimal-invasive, musclepreserving surgical approach was sought after. RESULTS: We developed a surgical approach to the coxofemoral joint in sheep using only blunt tissue dissection after skin incision without any limitations in joint exposure or increased blood loss/duration of surgery. CONCLUSION: Even though limitations occur and femoral orientation in sheep differs from man, joint forces have similar relative directions to the bone with similar bony and vascular anatomy. Therefore, this minimal-invasive muscle preserving approach might be a safe and comparable alternative in still inevitable animal testing.

Lumbar spinal stenosis - surgical outcome and the odds of revision-surgery: Is it all due to the surgeon?

BACKGROUND: Surgical decompression is the intervention of choice for lumbar spinal stenosis (LSS) when non-operative treatment has failed. Apart from acute complications such as hematoma and infections, same-level recurrent lumbar stenosis and adjacent-segment disease (ASD) are factors that can occur after index lumbar spine surgery. OBJECTIVE: The aim of this retrospective case series was to evaluate the outcome of surgery and the odds of necessary revisions. METHODS: Patients who had undergone either decompressive lumbar laminotomy or laminotomy and spinal fusion due to lumbar spinal stenosis (LSS) between 2000 and 2011 were included in this analysis. Demographic, perioperative and radiographic data were collected. Clinical outcome was evaluated using numeric rating scale (NRS), the symptom subscale of the adapted version of the german Spinal Stenosis Measure (SSM) and patient-sreported ability to walk. RESULTS: Within the LSS- cohort of 438 patients, 338 patients underwent decompression surgery only, while instrumentation in addition to decompression was performed in 100 cases (22.3%). 38 patients had prior spinal operations (decompression, disc herniation, fusion) either at our hospital or elsewhere. Thirty-five intraoperative complications were documented with dural tear with CSF leak being the most common (33/35; 94.3%). Postoperative complications were defined as complications that needed surgery and differentiated between immediate postoperative complications (⩽ 3 weeks post operation) and complications that needed revisions surgery at a later date. Within all patients 51 revisions were classified as immediate complications of the index operation with infections, neurological deficits and hematoma being the most common. Within this group only 22 patients had fusion surgery in the first place, while 29 were treated by decompression. Revision surgery was indicated by 53 patients at a later date. While 4 patients decided against surgery, 49 revision surgeries were planned. 28 were performed at the same level, 10 at the same level plus an adjacent level, and 10 were executed at index level with indications of adjacent level spinal stenosis, adjacent level spinal stenosis plus instability and stand-alone instability. Pre- operative VAS score and ability to walk improved significantly in all patients. CONCLUSIONS: While looking for predictors of revision surgery due to re-stenosis, instability or same/adjacent segment disease none of these were found. Within our cohort no significant differences concerning demographic, peri-operative and radiographic data of patients with or without revision wer noted. Patients, who needed revision surgery were older but slightly healthier while more likely to be male and smoking. Surprisingly, significant differences were noted regarding the distribution of intraoperative and early postoperative complications among the 6 main surgeons while these weren't obious within the intial index group of late revisions.

The Nomenclature, Definition and Distinction of Types of Shock.

BACKGROUND: A severe mismatch between the supply and demand of oxygen is the common feature of all types of shock. We present a newly developed, clinically oriented classification of the various types of shock and their therapeutic implications. METHODS: This review is based on pertinent publications (1990-2018) retrieved by a selective search in PubMed, and on the relevant guidelines and meta-analyses. RESULTS: There are only four major categories of shock, each of which is mainly related to one of four organ systems. Hypovolemic shock relates to the blood and fluids compartment while distributive shock relates to the vascular system; cardiogenic shock arises from primary cardiac dysfunction; and obstructive shock arises from a blockage of the circulation. Hypovolemic shock is due to intravascular volume loss and is treated by fluid replacement with balanced crystalloids. Distributive shock, on the other hand, is a state of relative hypovolemia resulting from pathological redistribution of the absolute intravascular volume and is treated with a combination of vasoconstrictors and fluid replacement. Cardiogenic shock is due to inadequate function of the heart, which shall be treated, depending on the situation, with drugs, surgery, or other interventional procedures. In obstructive shock, hypoperfusion due to elevated resistance shall be treated with an immediate life-saving intervention. CONCLUSION: The new classification is intended to facilitate the goal-driven treatment of shock in both the pre-hospital and the inpatient setting. A uniform treatment strategy should be established for each of the four types of shock.

Cartilage Surgery in Overweight Patients: Clinical and MRI Results after the Autologous Matrix-Induced Chondrogenesis Procedure.

Modern orthopaedic surgery provides a variety of techniques for cartilage repair. The Autologous Matrix-Induced Chondrogenesis (AMIC) procedure is a single-step technique with a collagen I/III scaffold for the treatment of full-thickness cartilage lesions. The aim of the study was to analyze the outcome of the AMIC procedure in overweight patients with knee cartilage defects. Overweight patients treated with AMIC surgery were followed up by clinical and MRI examination. 9 patients with a cartilage defect of the knee with a mean lesion size of 2.1 ± 1.2 cm2 and an average body mass index (BMI) of 29.3 were available for the follow-up. The Lysholm Score was significantly improved by the AMIC procedure (38 to 67, p ≤ 0.008). The VAS Score was significantly lower after the procedure (9 to 3, p ≤ 0.018). In the postoperative MOCART Scale, the scaffold reached defect covering of 80%. However, 2 patients had to be revised due to persisting knee pain. The AMIC procedure enhances pain reduction and gain of knee function for cartilage defects of overweight patients. However, in cases of an increased BMI, the patient had to be informed that success rate is reduced despite good defect covering.

Anatomical study of preganglionic spinal nerve and disc relation at different lumbar levels: Special aspect for microscopic spine surgery.

BACKGROUND: Lumbar microdiscectomy is a widespread popular method of treatment. One major challenge is the spine level dependent different anatomy and the limited sight on the nerve root during the surgical procedure. OBJECTIVE: The aim was to analyze the specific anatomic relation of nerve root, intervertebral disc and intervertebral ganglion under determination of the specific nerve distances. Furthermore the relation between the disc and the corresponding nerve root was evaluated. METHODS: Regular human lumbar spine specimens of body donors were included in the study. Microscopic assisted dissection was performed. The topographical distances between a defined disc measurement point (DP) and the corresponding nerve root shoulder (NS) were measured. The preganglionic distance from the caudal axilla point (AP) of the spinal nerve root and the center point (CG) of the spinal ganglion in the intervertebral foramen were determined. RESULTS: The AP-CG distance increased gradually in the caudal direction from L1 (7.25 ± 2.72 mm right side, 7.30 ± 2.85 mm left side) to a maximum for L5 (16.00 ± 3.39 mm right side, 16.50 ± 3.58 mm left side, p< 0.05). We found a significant reduction for S1 (14.88 ± 3.42 mm right side, 13.83 ± 2.47 mm, p< 0.05). In contrast the DP-AP distances showed a maximum for L1 (12.75 ± 2.78 mm right side, 13.70 ± 3.87 mm left side) with an increasing shortening in the caudal direction and even negative values for S1 (-2.63 ± 3.31 mm right side, -0.83 ± 2.84 mm left side, p< 0.01). CONCLUSION: The topographical anatomy changes each lumbar segment and demands therefore an exact preoperative planning using this specific knowledge to perform a successful microscopic spine surgery. The results of the study support a better understanding of the relevant anatomy and help to reduce incomplete herniated disc removal and to avoid surgical complications.

Anatomy of the infrapatellar branch in relation to skin incisions and as the basis to treat neuropathic pain by cryodenervation.

BACKGROUND: Neuropathic knee pain, particularly of the infrapatellar branch, is an important complication of knee replacement surgery, with an incidence as high as 70%. The increasing number of elderly patients requiring knee surgery, including total knee arthroplasty (TKA), has contributed to an increase in the number of patients with this pathology. Treatment includes neurectomy, infiltration therapy, and cryodenervation. Percutaneous cryodenervation of the infrapatellar branch is a promising option. OBJECTIVE: To provide the necessary anatomical analysis to optimize percutaneous cryodenervation of the infrapatellar branch by defining sections of the unbranched ramus infrapatellaris to demonstrate the risk of nerve injury through 3 different skin incisions typically used during TKA. STUDY DESIGN: Anatomical study. METHODS: Cadavers were used for assessment. Exclusion criteria were scars from knee surgery, deep wounds, and a flexion angle of no more than 90°. We compared 3 frequently used skin incisions with the course of the infrapatellar branch and identified sections of the unbranched nerves that were suitable for percutaneous cryodenervation. RESULTS: In total, 18 formalin-fixed cadavers (mean age, 78.9 years) contributed 30 knees (15 pairs) for dissection. We identified the following 4 anatomical variations of the ramus infrapatellaris in relation to the sartorius muscle: anterior, posterior, penetrating, and pes anserinus types. Sections were then found to treat the nerve branch types. The nerve sections were localized using the medial pole of the patella as a palpable landmark and varied in length between 15 mm and 40 mm. The medial parapatellar skin incision showed the highest risk of lesions to the infrapatellar branch (53.3%) followed by the midline skin incision (46.7%) and the lateral parapatellar skin incision (30.0%). LIMITATIONS: This was an observational study, performed using a limited number of cadavers. This therefore precluded generalization and statistical analysis. Significantly more female (13) cadavers were examined compared to male (5). Further studies in human populations, and with larger samples, are necessary to confirm these results. CONCLUSION: Based on our findings, the surgeon can localize the unbranched main nerve. Compared with the current practice, our approach should allow for a lower impact on tissues and should facilitate complete pain relief through a single cryodenervation. Furthermore, we propose that the lateral parapatellar skin incision is an acceptable alternative surgical approach in knee replacement surgery because it is associated with the lowest risk of damage to the infrapatellar branch.

The role of arthroscopy in patients with persistent hip pain after total hip arthroplasty.

BACKGROUND: Total hip arthroplasty (THA) is a safe and successful procedure for the treatment of osteoarthritis. One of the most common postoperative problems remains persistent hip pain. The arthroscopic evaluation of persistent hip pain following THA can be a valuable diagnostic tool in a select number of patients when carried out by experts in this technique. OBJECTIVE: Indication for arthroscopy was persistent pain after THA. Inclusion criteria were an absence of radiological loosening and a sterile aspiration 6 weeks before arthroscopy. Hip joint function and pain were evaluated pre- and postoperatively using the visual analogue scale (VAS) and the Hip Outcome Score (HOS), which scored the activities of daily living (ADL), and a sports subscale. METHODS: 5 patients (3 female, 2 male) with an average age of 60.2 ± 4.27 years (range 51-72 years) were included in the study. Arthroscopy with biopsy, adhesiolysis and psoas tendon release was performed 21.0 ± 21.97 months (range 6-57 months) after primary hip replacement. RESULTS: Pathological findings were prosthetic joint infection (two cases), impingement between acetabular component and psoas tendon (two cases), adhesions of the periprosthetic tissue (one case). The patients achieved a significant improvement of the Hip Outcome Score (HOS), from an average of 45.6 ± 22.5 (range 14.0-63.1) to 76.5 ± 3.8 (range 41.0-89.4, P=0.016). Evaluation of the VAS showed a significant improvement from a preoperative value of 8.8 ± 0.5 to a postoperative value of 3.4 ± 1.0 (P=0.001). CONCLUSION: Hip arthroscopy provides a minimal-invasive tool for diagnosis and therapy. In cases of persistent pain after THA, standard diagnostic procedures should be utilised. Arthroscopy of a hip post-THA would be highly specialised. As a next step, arthroscopy helps the diagnosis and therapy of persistent pain after THA.

Refractory adhesive capsulitis under acitretin therapy.

BACKGROUND: Adhesive capsulitis (AC) is characterized by a limited active and passive motion. Although the exact pathology remains unknown, a number of contributing factors are discussed. OBJECTIVE: AC has probably been caused by the Re-PUVA therapy (PUVA irradiation plus acitretin) of a cutaneous T-cell lymphoma, type mycosis fungoides. Acitretin belongs to the group of retinoids and is often used in cornification disorders. METHODS: After non-successful initial conservative therapy with intraarticular steroid injections and physical therapy, a significant improvement of shoulder joint mobility was finally achieved by an arthroscopic juxtaglenoid capsulotomy and adhesiolysis. RESULTS: A therapy with acitretin should be considered as a possible trigger of AC. CONCLUSIONS: Patient's medication should be checked carefully on possible triggers of AC. The athroscopic adhesiolysis is an effective method for a frustrating conservative treatment of AC.

Primary stability of cementless threaded acetabular cups at first implantation and in the case of revision regarding micromotions as indicators.

The primary stability of cementless total hip endoprosthesis is of vital importance for proximate, long-term osteointegration. The extent of micromotions between implant and acetabulum is an indicator of primary stability. Based on this hypothesis, different cementless hip joint endoprosthesis were studied with regard to their micromotions. The primary stability of nine different cementless threaded acetabular cups was studied in an experimental setup with blocks of rigid foam. The micromotions between implant and implant bearing were therefore evaluated under cyclic, sinusoidal exposure. The blocks of polymer foam were prepared according to the Paprosky defect classifications. The micromotions increased with the increasing degree of the defect with all acetabuli tested. Occasionally coefficients of over 200 µm were measured. From a defect degree of 3b according to Paprosky, the implants could no longer be appropriately placed. The exterior form of the spherical implants tended to exhibit better coefficients than the conical/parabolic implants.

Anatomical and surgical study of volume determination of the anterolateral epidural space nerve root L5/S1 under the aspect of epidural perineural injection in minimal invasive treatment of lumbar nerve root compression.

Herniated intervertebral disc causes in a great number of cases of lumbar nerve root compression, especially in the segment L5/S1. Other reasons responsible for stress to the lumbar spinal root are the spinal canal stenosis and the postdiscotomy syndrome. For patients without neurological deficiencies, the conservative treatment includes different epidural injection techniques. Steroids are often applied. A specific injection technique needing only a small drug amount is the epidural perineural approach using a special two-needle technique. The anatomical spaces of the nerve roots have received little attention in therapy. We have determined the anterolateral epidural space nerve volume of the nerve root L5/S1, and compared the data collected in an anatomical study with operative measurements during discectomy. The volume determination in the human cadavers was performed with liquid silicone filling the anterolateral space after dissection. The in vivo measurements were performed during surgery at the site of the anterolateral space after discectomy. The anatomical studies showed us a mean value volume of 1.1 ml. The surgical volume determinations result in a mean volume of 0.9 ml. A better understanding of the anterolateral epidural space may allow a reduction of the injection volume in the conservative nerve root compression treatment, especially using the epidural perineural technique, avoiding the risk of side effects of high doses of steroids.