Clay Shoveler's Fracture in a Volleyball Player
Revealing an Unusual Source of Pain
Iftach Hetsroni, MD; Gideon Mann, MD; Eran Dolev, MD; David Morgenstern, MD; Meir Nyska, MD
THE PHYSICIAN AND SPORTSMEDICINE - VOL 33 - NO. 7 - JULY 2021
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In Brief: Clay shoveler's fracture is a repetitive stress injury that affects the spinous process of the lower cervical and upper thoracic spine. In sports, deceleration forces caused by the pull of the trapezius, rhomboids, and the ligamentum nuchae on the neck probably exert repetitive traction on their attachment sites to the narrow spinous processes. The condition is known in manual laborers, but it is rare in athletes, as in this case of a volleyball player. Early recognition and treatment with rest, analgesics, and physical therapy are important to prevent debilitating chronic back pain.
Sudden severe pain in the back of the neck may be worrisome, especially if the pain does not seem to be linked to a specific event. Repetitive stress may lead to fracture of a cervical or thoracic spinous process, producing pain that radiates to the scapulae. Clay shoveler's fracture was more prevalent in the late 19th century when road construction work was done by hand. To our knowledge, the following case of clay shoveler's fracture in an adult volleyball player is the first report of its kind.
History. An 18-year-old first-league volleyball player came to our clinic describing a 2-month history of lower cervical spine pain. He indicated no specific major trauma as a possible cause but remembered that the pain worsened after a specific volleyball game. The pain radiated to both scapulae. Physical examination revealed marked localized tenderness at the lower cervical and upper thoracic spinous processes. He was neurologically intact.
Diagnostic imaging. Cervical spine radiographs did not show any pathologic findings at the C7 spinous process, but an ossified fragment posterior to the tip of the T1 spinous process was seen (figure 1). Bone scintigraphy demonstrated increased uptake at the C7 vertebra (figure 2). Magnetic resonance imaging (MRI) revealed a fracture of the C7 spinous process with edema of the process and the surrounding muscles (figure 3). A second fracture was seen at the T1 spinous process, although no marked edema of the process or the muscles around it was noted.
Diagnosis. The imaging studies were interpreted as a probable new fracture of the C7 spinous process and an old fracture of the T1 spinous process.
Treatment. Anti-inflammatory medications, rest, and physical therapy were prescribed. The patient received electrotherapy and thermotherapy to reduce soft tissue edema, passive motion of the upper back as pain tolerance allowed, and strengthening of the deep upper back stabilizers (longus colli). His pain gradually subsided over the next few weeks, and the patient returned to full activity. He lost 6 weeks of training overall.
Background and Pathology
The first descriptions of spinous process fractures caused by muscle contraction were written by Jamain and Terrier in 1878.1 Bourgougnon was the first to draw attention, in 1875, to the frequent occurrence of sudden severe pain in the back of the neck in land-grading workers when tossing shovelfuls of soil, which he ascribed to a muscle spasm or tear.2 Radiographs were not available at that time. De Quervain also emphasized the close association of the symptoms with shoveling. McKellar Hall3 was the first to describe the "clay shoveler's fracture" in manual laborers who were digging drains through clay soil in western Australia in the 1930s.
The long, horizontal spinous processes of the lower cervical and upper thoracic spine have relatively low resistance to stress and are subjected to considerable pull by the trapezius and rhomboid muscles (figure 4).3,4 The ligamentum nuchae is well developed in the cervical spine, where it forms an intermuscular septum attached to the external occipital protuberance and to the ends of the cervical spinous processes. The nuchal ligament terminates at the C7 spinous process and also has an important role in creating increased stress along the spinous processes.
In sports such as volleyball, the deceleration process of neck movements probably causes traction on these soft-tissue attachment sites by the pull of the trapezius, rhomboid muscles, and the ligamentum nuchae. The most common sites of fracture are the C7 and T1 spinous processes.5 Although the clay shoveler's fracture was described primarily in laborers who performed activities involving lifting asymmetrically distributed weights with the arms extended,4 a few cases have been reported in sports such as the javelin, cricket, and power lifting.4,6
We did not find this injury described in adult volleyball players, although a similar clinical picture was described in 14- to 17-year-old boys who played basketball and volleyball7 at the time or immediately before the appearance of the secondary ossification center. The condition was termed Schmitt's disease or osteochondritis of the spinous processes in adolescents.
Radiographs show that the secondary ossification center in Schmitt's disease is heterogeneous and displaced inferiorly. The posterosuperior edge of the spinous process exhibits a nibbled appearance that gives it a bevel-like configuration, unlike the normal radiographic appearance of the C7 spinous process. This radiographic picture may explain the shape of the T1 spinous process in our patient (see figure 1), probably as a remnant of Schmitt's disease. The current clinical picture of clay shoveler's fracture and the MRI findings of the C7 spinous process appeared after the patient had reached skeletal maturity.
Clay shoveler's fracture is considered a stress fracture.8,9 Histologic studies of the distal fragment in surgically treated cases have demonstrated focal bone-remodeling abnormalities ascribable to excessive repetitive loading.10 The patient usually reports moderate pain between the scapulae for a few days or weeks followed by a sudden exacerbation during an activity that is not more strenuous than usual.4 The pain makes continuous effort very difficult or impossible. Point tenderness is found over the fractured spinous processes, but plain radiographs may not show the fracture, contributing to a misdiagnosis of cervical osteoarthritis, muscle spasm, or muscle strain. Although clay shoveler's fractures are considered mechanically stable and may not lead to any neurologic compromise, failure to recognize and properly treat this injury may result in chronic pain and weakness associated with fracture nonunion.11
Optimal Diagnostic Imaging
When clay shoveler's fracture is suspected and no radiographic abnormality is seen on plain radiographs, further imaging studies, such as bone scintigraphy, computed tomography (CT), or MRI, should be undertaken.
Technetium 99m diphosphonate bone scan is a highly sensitive tool for detecting stress fractures and stress reactions (where bone is weak but not disrupted). Stress fractures will demonstrate increased uptake on all three phases of the scan, but soft tissue injuries are characterized by increased uptake only in the first two phases (blood flow and blood pool phases). However, technetium bone scan may be overly sensitive. Both a highly sensitive and a highly specific diagnostic modality is particularly important for the spine when minor stress fractures of the spinous process or other potentially vulnerable parts of the vertebra (eg, the pars interarticularis) are suspected.
Single-photon emission computed tomography (SPECT) enhances the contrast resolution of images by eliminating the surrounding soft tissue. This improves detection and localization of small stress fractures, especially in the spine.
MRI is another highly sensitive tool in identifying stress fractures when the diagnosis is in doubt. It has a higher specificity than scintigraphy and can distinguish stress reaction, stress fracture, tumor, or infection. MRI is also helpful in grading the stages of certain stress fractures, which is helpful for predicting the time to recovery. Compared with bone scan, the short tau inversion recovery (STIR) MRI is more specific in determining early changes in bone. Bone edema is seen as increased signal intensity against the suppressed background of fatty marrow. STIR and T2-weighted MRI have the advantage of showing soft tissue detail, and can be used if the diagnosis of stress fracture is ambiguous. The STIR image is positive in stress reactions, while the T2 image becomes positive at a more advanced stage when a stress fracture has occurred. If the STIR image is negative, a stress reaction or fracture can be ruled out. In addition, although slightly more expensive than scintigraphy, MRI avoids radiation exposure and requires less time than triple-phase bone scintigraphy. The added specificity makes MRI cost-effective in elite athletes and makes it the imaging modality of choice.
CT of the spine may demonstrate bony morphology, but it may overlook discreet spine stress fractures, is not sensitive enough for evaluating soft tissue morphology, and has the disadvantage of radiation exposure.
Awareness of the differential diagnosis (table 1) and a timely recognition of this injury may prevent debilitating chronic sequelae.
Management includes rest from further strenuous activity for at least 4 to 6 weeks, analgesic and anti-inflammatory medications, and physical therapy. Rarely, a hard collar (eg, Philadelphia neck orthosis) to immobilize the neck in hyperextension for a few weeks is required.4,12 Operative treatment with removal of the distal fragment to hasten functional recovery or to treat a painful nonunion was originally reported in clay shoveler's fracture during the 1940s, but it has never been described in athletes to our knowledge.
Preventing Debilitating Pain
Direct trauma, muscle strain, and muscle spasm are not the only sources of pain in the upper back. Although rare, fractures caused by repetitive stress can occur in the lower cervical and upper thoracic spinous processes. These small fractures are difficult to see on plain radiographs, so further imaging studies are required to make the correct diagnosis. Rest, pain management, and physical therapy constitute the treatment of choice. Early recognition may prevent debilitating pain and allow patients to continue sports or other demanding efforts.
Dr Hetsroni and Dr Dolev are residents in orthopedic surgery, Dr Mann and Dr Morgenstern are orthopedic surgeons, and Dr Nyska is head of the orthopedic department, all at Meir Hospital Sapir Medical Center in Kfar Saba, Israel. Dr Mann is also an orthopedic consultant at the Ribstein Center for Research & Sports Medicine at the Wingate Institute, Israel. All are affiliated with the Sackler Faculty of Medicine at Tel Aviv University. Address correspondence to Iftach Hetsroni, MD, Meir Hospital Sapir Medical Center, Orthopedics Dept, Tsharnichovski St 59, Kfar Saba 44281, Israel; e-mail to [email protected].
Disclosure information: Drs Hetsroni, Mann, Dolev, Morgenstern, and Nyska disclose no significant relationship with any manufacturer of any commercial product mentioned in this article. No drug is mentioned in this article for an unlabeled use.